Digital transmission system (DTS)

4

Content

Introduction

1. Analyses o the current situation on the project and the development of their technical realization

1.1 Brief description of the existing zonal area network

1.2 Project formulation of the problem

1.3 Basic requirements for communication lines

• 1.4The lines of communication and the basic properties of the fiber optic link
• 1.5 Comparison of characteristics and selection of the desired type of optical cable
• 1.6 The choice of construction method, the route for laying fiber-optic

1.7 Primary BCC Network

• 1.8 Calculation of the required number of channels
• 2. The technical part
• 2.1 Fiber -optic comminication lines

2.1.1 Overview FOL

2.1.2 Structural features FOC

2.1.3 Distribution of light beams in optical fibers

2.1.4 Modes propagating in optical waveguides

2.1.5 Single-mode optical fiber

2.1.6 Constant distribution and phase velocity

2.1.7 Calculation of the main characteristics of the fiber optic link

2.2 Digital transmission systems

2.2.1 The concept of building a modern transmission systems

2.2.2 Transmission systems of PDH, characteristic features

2.2.3 SDH Standard

3. Working documents

3.1 Proposals for the selection of equipment for communication

3.1.1 The main function module SDH networks

3.1.2 Proposal for the selection of the radiation source and photodetector

3.2 Welding questions, and measurement of the optical fiber connection

4. Occupational Health and Safety

4.1 Analysis of dangerous situations

4.2 Creating the optimal working conditions of the operator

4.3 Calculation of illumination LC

4.4 Verification ground settlement

5. Environmental protection

5.1 General

6. Feasibility study of the project

6.1 General

6.2 Investments

6.3 Operating costs

6.4 Operating income

6.5 Gain on sale of services

6.6 Payback period

6.7 Profitability

Conclusion

Application A

Application B

Application C

Bibliography

Introduction

Communication of Kazakhstan to a qualitatively new stage of historical development is determined by the new geopolitical situation. The basis of Kazakhstan's telecommunication is interconnected communication network, ensuring the provision of users of telecommunications services in the country.

Interconnected communications network - the complex conjugate technology telecommunications public networks and private networks with a common centrally managed, regardless of departmental affiliation and forms of ownership.

The first fiber-optic communication line (FOCL) in the CIS countries were built in the early 80-ies of XX century, based on the use of multimode optical fiber, mainly it was the connecting link between the nodes of the СTS network using a 30-channel digital system transmission 'Sonata'. Although originally mortgaged service life FOCL was not less than 25 years, however, for the stable functioning of the transmission system required to maintain fiber-optic characteristics within acceptable limits.

The first fiber-optic trunks were laid mainly in the city and had a small extent, usually no more than 1-2 km. Inherent cable with multimode fiber mode dispersion of the signal, used for low-speed (2 or 8Mbit / s) transmission systems for short distances was a small amount and is not needed in the measurement. Locating a fault in the trunk of small extent, laid on the cable duct, made by visual inspection.

The situation changed radically with the advent of the 90-ies of XX century for telecommunication systems a single-mode fiber (having less kilometric attenuation and dispersion on the order of magnitude smaller compared to multimode fiber) and high-power laser sources. The length of the fiber-optic sections without of regeneration increased to tens of hundred kilometers, digital signal transmission rate, realized in the emerging systems of transmission of synchronous digital hierarchy (the SDH), reached 622Mbit / s (STM-4 level) and above. Also changed the concept of the construction of communication networks, have become the basic ring and mixed (ring + linear) topology, giving new opportunities to create backup routes of transmission of telecommunications traffic.

In Kazakhstan, the start of construction of the first fiber-optic lines with single-mode type optical fiber in the second half '90s, it was the main line of long-distance communication.

Digital transmission systems (DTS) are characterized by excellent information from analog systems properties. The main advantages of these systems are the following: a higher noise immunity, which can significantly alleviate the requirements for signal propagation conditions on the transmission line; be integrated messaging and switching systems; negligible impact of the transmission line parameters on the channel characteristics; the possibility of using modern technology in hardware DTS; the absence of the phenomenon of accumulation of noise and distortion along the transmission line; a simple terminal equipment as compared to equipment of transmission systems with frequency division multiplexing (FDM); ease of classification of information transmitted.

In this thesis the issues of modernization of the site zonal networks Stepnogorsk-KOCshetau based fiber-optic line. Operated on site equipment K-60 with a transmission medium (electrical cable) does not meet the requirements for the quantity and quality of channels.

1. Analyses of the current situation on the project and the development of their technical realization

1.1 Brief description of the existing zonal area network

On the considered one symmetrical lead-polyethylene cable 1x4x1,2 Stepnogorsk KOCshetau-laid plot, on which the work of analog transmission systems K-60P providing organization 60 channels. Here are the specifications and block diagram of channeling equipment K-60 (Figure 1.1).

Cable1

Cable2

PTS-DS-60-hour dial tone and differential systems; STS-60-hour personal drive; EGR-hour group transformations; SLUK OP-hour linear amplifiers and equalizers; EASB-1-5-hour standardized generator equipment; BCSS-11-hour lead-switching equipment; SDP remote power rack; STS-7 intercom rack

Figure 1.1 Block diagram of a terminal station OC-60P

The transmission system of K-60P is designed for organizations sixty voice channels on the chains of the ISS and ICD symmetrical cables. In rail transport, it is widely used for working on cables INC. The communication system of two-strip cable, line spectrum frequencies is 12-252 kHz. Transmission distance of 12,500 km. The maximum length of re-receiving site on tonal frequency is 2500 km. To ensure such a range in the chain include supervised and unattended repeaters.

Nominal relative transmission rate in line without pre-distortion on all channels is -5 dB, the upper channel pre-distortion -1 dB, -11 dB on the bottom. To maintain the residual attenuation in the terminal equipment and intermediate stations DC has the automatic gain control AGC. The operation of the automatic gain control unit controls the current control frequency: 16 kHz - inclined, 112 kHz - the curved, 248 kHz - flat. At the terminal stations and the PMU-3 uses three-frequency (plane-inclined curved); GMS-2 - dual frequency (flat-sloping) AGC; on NUP - frequency-dependent groundwater AGC.

The greatest gain amplifier stations on the highest frequency to indulge in OP and the PMO is 61 dB, for NFA - 55 dB. Maintenance-free reinforcement points are placed along the highway after an average of 19 km, the PMU-2 - by 250-300 km, PMO-3 - through 500-600 km.

Terminal and served by amplifying points have local sources of supply, NFA are powered remotely from the PMO or OP.

The largest number of NFA between PMO (OP) in the organization of the remote power supply for wire-to-ground system is 12, according to wire-wire system - 6.

Additional information K-60 and the scheme of frequency conversion transmission system K-60P (Figure 1) are given at the end of the explanatory note [A.A.].

On the entire length of the communication line 5 established unattended amplifying points (UAP). Cable laid along the highway Stepnogorsk- KOCshetau (Figure 2) [A.A].

Remote power organized under the 'wire-wire', the power of 3 UAP - s made from KOCshetau remaining powered from the village. Stepnogorsk.

On the existing cable line and the precinct organized backbone intercom, as there is a telecontrol system-monitoring equipment.

The aging (about more than 20 years) and by external atmospheric influences polyethylene coating was porous, moisture-permeable, due to which cable parameters changed. Insulation does not meet the required standards, the integrity of the screen is brOCen, resulting in a deteriorated immunity, there were mutual influences and external influences. All this leads to deterioration of communication quality, and, as a consequence of consumer complaints.

On the entire length of the route, except clutches made in the construction of a cable line, a large number of joints resulting from mechanical damage to the cable.

All this leads to greater operating costs for repair and maintenance of existing communication lines, which mainly consist of transport costs and the costs associated with the acquisition of cable necessary to eliminate the frequent injuries, and attempts to bring the cable parameters to the required standards.

Operated transmission system K-60P taken out of production, and it is not available spare parts which are necessary for the replacement of the building blocks. As a result, we have to buy spare parts with similar dismantled, but serviceable systems. The aging and drying installation elements increases defectiveness equipment, resulting in deterioration of reliability.

In addition, the analog channels are used with limited range (0,3-3,4 kHz) and the presence of interference can not provide a large transmission rate required at this stage, for data transmission.

1.2 Project Formulation of the problem

As mentioned above (Section 1.1), there was a strong need for communication channels in this area, that is, to increase the bandwidth capacity of the link. In addition, one should also note that the quality of communication in this area is poor.

Therefore, in this project it is necessary to develop the following issues: selection of the route for laying fiber-optic; definition of requirements in communication channels at a projected fiber optic; choice of optical fiber and cable brands; calculation of the dispersion properties of the fiber and definition of the actual dispersion and attenuation in the line, the calculation of these data regenerator section length; offer a variety of communications equipment, with the necessary factors; Analysis of factors affecting the safety of the personnel working in the construction and operation of communication lines, as well as on the protection of the environment; determine the economic parameters of the project.

1.3 Basic requirements for communication lines

In general, the requirements of a highly modern technology to the telecommunications long-distance communication lines, may be summarized as follows:

- Implementation of communication at distances up to 12,500 km within the country and up to 25,000 ** for international communication;

- Broadband and suitability for the transmission of various types of modern media (television, telephony, data transmission, broadcasting, transmission and front pages of newspapers, etc., as well as modern, interactive forms of communication..);

- Protection of circuits against mutual and external interference, as well as storms and corrosion (electrical cables and optical fiber cables with metal elements);

- The stability of the electrical parameters of the line (electric cables), optical parameters (optical cables), the stability and reliability of the communication;

- Cost communication system as a whole.

Cable lines (electrical and optical) DLD is a complex technical structure, consisting of a large number of elements. Since the line is designed for continuous operation (tens of years and above) and her smooth operation of hundreds and thousands of channels should be provided (thread) connections, then all elements of linear-cable equipment, and first of all the cables and cable accessories included into a linear signal path, high demands. Selecting the type and design of the link is determined by not only the process of propagation of energy along the line, but also the need to protect the adjacent RF circuit from mutual interferences (electrical cable). Cable dielectrics are selected on the basis of the requirements to ensure maximum communication range in the HF channels with minimal losses.

In accordance with this cable machinery developed in the following areas:

1) Development of coaxial systems to organize the powerful beams of communication and transmission on single-cable connection system, cable television programs.

2) Development and implementation of advanced communication OC for a high number of channels and does not require for its production of scarce metals (copper, lead).

3) The widespread introduction in the cable equipment of plastics (polyethylene, polystyrene, polypropylene, etc.), Have good electrical and mechanical characteristics and to automate production.

4) The introduction of aluminum, steel and plastic casings instead of lead. Skins should have the integrity and ensure the stability of the electrical parameters of the cable over the entire service life.

5) The development and introduction of cost-effective designs intra communication cables.

6) Creating a shielded cable, securely protecting transmitted information on them from external electromagnetic influences and thunderstorms, in particular cables in double membranes.

7) Increase of dielectric strength of cables of communication. Modern cable (electrical and optical cable with metal elements) should have the same time as the high-frequency properties of the cable, and the power of an electric cable, and capable of transmitting high-voltage currents for remote unattended power regeneration (amplifier) items over long distances.

1.4 The lines of communication and the basic properties of the fiber optic link

At the present stage of development of society in the conditions of scientific and technological progress continually increase the amount of information. As shown by theoretical and experimental (statistical) research, communication industry production, expressed in the amount of transmitted information increases in proportion to the square of the growth of the gross domestic product of the economy. This is determined by the need to expand the relationship between the various links of the national economy, as well as increasing the amount of information in the technical, scientific, political and cultural life of society. Increases the demands on the speed and quality of transmission of a variety of information, increasing the distance between callers. Communication is essential for the operational management of the economy and of public authorities to improve the country's defense and to meet cultural and social needs of the population.

In an era of scientific and technological revolution, communication has become an integral element of the production process. It is used for process control, electronic computers, robots, industrial enterprises t. D. An essential and one of the most complex and expensive coupling elements are link (LAN), which transmits the information electromagnetic signals from one subscriber (station transmitter , regenerator, etc.) to another (the station, the regenerator, and a receiver r. h.) and back. It is obvious that the effectiveness of the communication systems is largely determined by the quality of medicines, their properties and parameters, as well as the dependence of these quantities on the frequency and impact of various factors, including the third-party interferences of electromagnetic fields.

There are two main types of drugs: the line in the atmosphere (radio link RL) and the guide link (link). Below are the main types of opportunities and common rail communication systems (Table 1.1)

Table 1.1 Frequency-classification systems and radio guide

Note: * According to the bands conducted experimental work on the development in the field of telecommunications and radio.

A distinctive feature of the guide lines is that signals propagating therein from one user (station apparatus, the circuit element and the like. D.) To another is carried out only by specially created circuits and paths PM forming guide system for transmitting electromagnetic signals in a predetermined direction due to the quality and reliability.

Currently, communication links are transferred from the DC signals to an optical frequency range and the operating wavelength range extending from 0.85 microns to hundreds of kilometers.

There are three main types of drugs: Cable (TC), air (VL), optical fiber (fiber optic). Cable and overhead lines are wired lines in which the system guides the system image 'conductor-insulator', and fiber-optic lines are dielectric waveguides, guiding system consisting of dielectrics with different refractive indices.

Fiber-optic lines are systems for transmitting light signals of the microwave wavelength range from 0.8 to 1.6 microns on optical cables. This type of links is seen as the most promising. The advantages of fiber optic links are low loss, high bandwidth, low weight and compact dimensions, the savings of non-ferrous metals, high degree of protection from external interference and. Below (Table 1.2) shows the comparative characteristics of different guides on the number of channel systems, as well as to the range.

Table 1.2- Number of communication channels for different guide systems

Note: JV with PDH and SDH ** - transmission system supporting PDH and SDH technology, working on the optical cable.

Conclusion: In view of the major requirements for the communication lines, and comparing the characteristics of the various communication lines (with the main fiber-optic properties) from the land-zone network Stepnogorsk KOCshetau proposed upgrade link based on optical cable.

1.5 Comparison of characteristics and selection of the desired type of optical cable

Optical communication cables perform essentially the same function as conventional cables.

In accordance with the adopted in most countries of the structure of construction of communication network, appointment, conditions of use and placement of the OC are divided into trunk, zonal and vnutriobektnye.

Since the OC less durable than traditional cables, they must be protected from the harmful effects of the environment and human activities. These effects include: mechanical stress - tension, bending, compression, torsion, shock; changes in temperature, the penetration of water, prolonged exposure to mineral oil and fire, rodents. The specific design provides protection against these effects by selecting the appropriate cable designs and measures for additional protection.

Conditions for the existence of cables to the trunk, internal, local, facility (LAN) communication networks are different, and the design can be used pretty much different from each other in design, not only the core but membranes and integument. So, OC backbone can be laid directly in the ground, in cable ducts, sewers, tunnels, in the aquatic environment (rivers, lakes, sea), in the air. Most of the cables intrazonal and local networks are in similar circumstances. The much lighter work OC under site-networks, mostly laid before the premises [17].

OC zonal serve to organize multi-channel communication between the regional center and districts with communication range up to 250. Gradient used 50/125 fiber sizes. Wavelength 1.3 ... 1.5 [9].

When choosing a cable design should take into account that the zonal cables are designed with a shaped core.

Zonal cables are used to connect the regional center with the districts and towns of the region. The communication range is usually within a hundred kilometers.

They are made as optical cables zonal communication in which remote power circuit separated from the armor wires and aluminum screen located inside the cable. The cable may comprise 4, 8 or more fibers [9].

Currently, domestic (Russian) cable industry has mastered proiz¬vodstvo optic cables of virtually all types and purposes. These cables meet the requirements of international standards and are made of fibers optiche¬skih foreign proizvodstva.Vse used OB meet the standards of the ITU-T (ITU-T) G.651-G.654. For making OC applied as otechest-governmental as well as imported materials of high quality. Optical fibers po¬stavlyayutsya following well-known companies - Corning Incorporation (USA), OFC - Optical Fiber Solution (formerly a division of LUCENT TECHNOLOGIES, owned by Furukawa now located in the United States), Fujikura (Japan), Alcatel (France), which produces optical fibers type TeraLight, Sumitomo (Japan).

In our country, only just adjusted the production of the cable (optical) products and is mainly used for telecommunication purposes cables foreign and Russian manufacturers. Characteristics of foreign manufacturers of cables are given in the form of a table (Table 1) [PA].

This project proposes to use cable products in Russia.

On the basis of the above fibers (. ITU-T standard (ITU-T) G.651-G.654), fiber optic cables in Russia produce fourteen enterprises [23]:

- JV 'Svyazstroy FFS-1,' Fiber Optic Cable Company (VOCK), co-founder of OFC (USA), Voronezh;

- JV 'Moskabel-Fujikura' (IFC), the co-founder of Fujikura (Japan);

- JV 'Samara Optical Cable Company' (JPAC), Samara, co-founder of Corning Inc. (USA);

- CJSC 'OCS01' St. Petersburg;

- LLC 'Opten' St. Petersburg;

- CJSC 'Saranskkabel-Optics', Saransk,

- JSC 'Sovkabel-Optics', St. Petersburg;

- Ltd. 'Elix-Cable', Moscow;

- CJSC 'Yauza cable', Moscow;

- LLC 'Eurocable', Moscow;

- CJSC 'TRANSVOC' Borovsk, the Kaluga region;

- JSC NF 'Wiring harness', Moscow;

- Company VNIIKP-OPTIC, Moscow.

One of the largest Russian companies producing optical cables, is a national firm AONF 'Wiring harness'. This plant produces almost all types of fiber optic cables for terrestrial PLAYBACK - from the trunk and hanging up intrabuilding OC, and OC to vnutristoechnyh compounds. Figure 1.2 shows a cross section of several types of main OC.

Figure 1.2 Optic trunk cables manufactured by JSC NF 'Wiring harness'

Cables type OCBS-T (Figure 1.2) are intended for laying in grounds of all categories, including rodent infected (except soils subject to low temperature deformations), in water for installation over river crossings and navigable rivers deeper than two meters in cable ducts , tubes, blocks, collectors, on bridges and in cable shafts. This type is OC on the outside is covered with a polyethylene membrane, which has a steel wire armor, and under it - the armor of corrugated steel tape.

Figure 1.2 b shows a section OC OCB-M ... OCNB M types. This type of cable has the same purpose. As the power element it uses steel wire or fiberglass rod (center). The outer cable sheath is made of conventional polyethylene or polyethylene, flame retardant. Under the shell there is a steel wire armor.

Cable type OCB-T, shown in Figure 1.2 and has an outer shell made of polyethylene, which is located under the steel wire armor. All of these types are based on OC singlemode OB damped 0.22 dB / km at a wavelength of 1550 nm. their main characteristics are incorporated in the names of the cables:

OCSBS 6,0-10-0,22-8-T - is an optical cable, steel wire armor, the diameter of the central tube (6.0), the core diameter RH (10), the damping RH - 0.22 dB / km, 8 - the number of fibers. Other design parameters OC trunk shown in Table 1.3.

Table 1.3 Constructive parameters of main production OC NF ZAO 'Wiring harness'

1.3 Table continuation

As the most suitable and satisfying the requirements of graduate design, choose the brand cable OCBST 6,0-10-0,22-8.

1.6 The choice of construction method, the route for laying fiber-optic

In Russia (and CIS), including Kazakhstan, the following options for laying fiber optic link:

- Laying in wOC primer in protective polyethylene pipes (I);

- Laying FOC in protective plastic conduits and symmetrical copper cable to solve the distillation, interoffice communication and signaling circuits in liquidation communication overhead line (II);

- Suspension FOC transmission line supports up to 10 kV, and supports high-voltage lines of automatic block system (III);

- Suspension FOC on the contact rail network supports (IV). Below is a table that compares key indicators.

The following table 1.4 compared methods of laying OC on the basic parameters.

Table 1.4-A comparison of methods for laying OC key indicators

The method directly into the ground along the railways and roads unprotected against mechanical damage and rodents. However, the method is facilitated by direct burial cable service link. In addition, reduced capital and operating costs. The service life of 20-25 years.

A method of laying cable in the ground in a plastic pipe protects against mechanical damage and rodents. The service life of fiber-optic cable in this case is 40-45 years. Capital and operating costs are greater than the method for directly into the ground.

If the suspension on catenary poles electrified railways, as well as supports high-line power companies will need to pay for their rent and electricity grids corresponding fee optic cable embedded in the ground wire is more expensive than conventional optical cable. This increases the capital costs and operating costs. Term of suspension cable service is 12-15 years, and difficult maintenance of cable lines.

Of the above methods choose II method of laying cable in the ground in a plastic pipe along the road, as in this case, easier maintenance of the cable lines and repair compared with overhead cables, protected from mechanical damage and rodents lifetime longer than that of both methods . This provided access roads maintenance personnel to places of cable laying and the CHP, and in case of damage to the surgical removal of a fault on the line.

The presence of settlements in the path of the track makes it possible to accommodate unserved regeneration areas and the use of existing facilities available telecommunications nodes, which significantly reduces the amount of construction work, and helps to reduce the cost of construction of the road in general.

Depth of the underground installation of optical as well as electrical and 1.2 m. Cable water crossings can be performed by laying under water, on the bridge or by the suspension on the supports. The most reliable is the laying of submarine.

To develop the plan of construction and financial estimates specify the path of receipt of goods for construction, the possibility of using the existing warehouses and handling areas, the deployment of new sites and warehouses, distance methods of delivery of materials to the warehouses, the prices of local materials, etc.

Referring to the map area (Figure 1) we see that the only viable option is obvious route. This option cabling along the highway connecting the city of Stepnogorsk - KOCshetau. [PA].

The total line length is 251 km, the length of the areas: Stepnogorsk - Makinsk - 141 km; Makinsk - KOCshetau - 110 km.

Railway track laid at a distance of 30-60 meters (depending on the specific local conditions) from road axis.

In Akmola region is dominated by flat terrain, it allows you to lay the cable in the main mechanized way. In more detail the organization of railway crossings, as well as mechanized methods cabling discussed in the relevant chapter of the diploma project.

1.7 Primary BCC network

To construct a communication network are required so-called transmission system, ie apparatus through which connection lines for creating channels and group paths. And then arrange of lines and nodes and terminal stations, primary and secondary telecommunications network.

Primary networks consist only of lines, regeneration (amplification) and channeling equipment at the stations. Secondary network comprise further switching nodes allowing to switch communication channels to multiple destinations. But already on the basis of secondary networks are numerous communication services, providing a variety of services. Communication lines laid between the cities and in the major cities, intermediate regeneration (amplifier) ??Items endpoints - all primary network, serving for standard analog and digital channels and paths.

Primary BCC network (interconnected network) is divided into the trunk, zonal and local area network (Figure 1.2).

Figure 1.2 - Backbone, zonal and local primary network

Typical telecommunication channels have the same characteristics, regardless of at what portion of the primary network are formed: these characteristics are strictly standardized and accurately performed. Standardized telecommunication channels a lot, but we are referring only two: the analog channel voice frequency (VF channel) with a bandwidth of 0,3-3,4 kHz and the main digital channel, the bandwidth is 64 kbit / s. Along the lines of the primary network connection is formed such channels. You can create and broadband analog channels, digital channels and with greater bandwidth, but the vast majority of available channels is as follows.

the secondary network is organized on the basis of the above-mentioned basic channels: telephone, telegraph, data transmission, faxes. The number of telecommunication services is growing right before our eyes, and now their number was thirty. To name just a few: city, intercity and international telephone, telegraph subscriber (so-called 'TTY'), telex, teletex, telefax, bureaufax, videotex, etc.

Of course, the biggest secondary network and the most numerous services - telephone. Most of the PM and digital channels in the country (it is necessary to think and abroad) are used for the formation of telephone networks. Moreover, often thought (evidenced by many publications) that the telephone network - the only secondary network, the other is not there. In fact this is not true: there are telegraph network - work on them telex (subscriber telegraph) and telegraph service in all offices. Any data transmission network, and not only with the rate of 64 kbit / s, but higher speed, e.g. 2048 kbit / s (E1 channel).

1.8 Calculation of the required number of channels

This trail is part of the zone network, so the calculation takes into account the number of regional and district centers of population. Population in any regional center and the region as a whole can be determined based on census statistics. According to these data, the population of the city of KOCshetau for 2007-2008 amounted to 132.4 thousand people, and in Stepnogorsk -. 46.7 thousand people.. Population growth, taking into account is determined by the formula:

(1.1)

where H0 - population during the census thousand;. P - the average annual population growth in the area (taken as equal to 2-3%); T - period, defined as the difference between the designated year prospective design and the year of the census.

Year prospective design was adopted for 5-10 years ahead. This year the project planning stage to take 10 years to come. In accordance with this parameter T is determined by the formula:

T = 10 for + (Tm-T0), (1.2)

where Tm - year drafting; T0 - the year to which the data H0;

The average annual population increase in Akmola region accept equal to 3% (according to the statistics department). Using formula (1.2) define the parameter T:

T = 10 + (2016-2009) = 7, s

The population in the city of Stepnogorsk, according to (1.1) will be:

, thous. people

The population in the city of KOCshetau will be:

, thous. people

Considering that the telephone lines interurban and international communication are prevail, you must first determine the number of voice channels between specified localities. To do this, use the following formula:

N_TF=LK_Ty (1.3)

where: L and Я - constant coefficients corresponding to the predetermined fixed availability losses, loss usually assumed equal to 5%, while L = 1,3, and = 5,6; K_T - gravitation factor; y - specific load, that is, the average load of the one person, y = 0,08 Earl; m_a, m_b - the number of subscribers served by AMTS terminals, respectively, in points A and B.

The relationship between the selected terminal and intermediate points is determined on the basis of statistical data from enterprises due for the preceding design years. In practice, this relationship is expressed in terms of gravitation coefficient K_T, which, studies show, it varies widely, from 0.1 to 12%. The project gravitation coefficient K_T is assumed equal to 10%, ie K_T = 0,1.

In the future, the number of subscribers served by AMTS terminal, determined according to the population living in the service area. Taking the average coefficient of equipment of public telephones in KOCshetau equal to 0.8, in Stepnogorsk - 0.2 subscribers in AMTS zone can be determined by the formulas:

m_a¹=0,8H_Т¹, (1.4)

m_b²=0,2H_Т², (1.5)

Inserting data into the formula (1.4) and (1.5) define the number of subscribers served endpoints AMTS:

m_a¹ = 0,8188,77 = 151,016, thousand. people

m_в² = 0,266,583 = 13,3166, thousand. people

Using formula (1.3) determine the number of voice channels:

n_ТФ=1,30,10,08+ 5,6 = 133, channels

In the cable transmission line isolated channels and other types of communications: data wire, radio, etc., also take into account the transit channels. In this case, the number of transit links will not be taken into account, they will be taken into account when choosing a transmission system.

Since the number of channels for communication for various purposes can be expressed by the number of voice channels, i.e. VF channels, it is advisable to the total number of channels between the points expressed by the PM channels.

Generally, the total number of channels is calculated according to the simplified formula:

n = 2n_ТF, (1.6)

n = 1332 = 266, channel

This calculation was made without taking into account the number of backhaul. So if you take into account the transit flows as well as prospects for further development of the network and the possibility of damage which may be necessary to bypass the organization through this highway, then the projected line required transmission speed is 155 Mbit / s (1890 channels).

As the transmission system I suggest using SDH equipment operating over a fiber-optic cable.

The planned establishment of a communication scheme is shown in Figure 3 [PA].

The diagram also shows the required number of PCM streams to be allocated in the corresponding paragraphs.

2. The technical part

2.1 Fiber-optic communication lines

2.1.1 Overview FOL

In fiber optic transmission systems (FOTS) information is transmitted by electromagnetic waves of high frequency, approximately 200 THz, which corresponds to the near infrared range of the optical spectrum of 1500 nm. Waveguides, transferring the information signals to the FOTS is an optical fiber (s) that has the important ability to transmit light at long distances with low losses. Losses in the OB quantitatively characterized by attenuation. Speed ??and distance data transmission are defined distortion of optical signals due to dispersion and attenuation. Fiber-optic network - is an information network that links between the nodes which are fiber-optic communication lines. Technology of optical fiber networks in addition to the issues of fiber optics also cover issues relating to the electronic transmission equipment and its standardization, communication protocols, network topology issues and general issues of networking.

Optical fiber is now considered the most advanced physical medium for the transmission of information, as well as the most promising medium for transmission of large data flows over long distances. The grounds to think so derived from a number of features inherent in optical waveguides:

- Broadband optical signals due to the extremely high carrier frequency Hz. This means that the optical link can transmit information at a bit rate of the order / s (1Tbit / s). In other words, a single fiber can transmit 10 million simultaneous phone calls and a million video. The data rate can be increased by transmitting information in two directions, as the light waves can propagate in the same fiber independently. Furthermore, in an optical fiber can propagate light signals of two different polarizations, which allows to double the capacity of an optical link. To date, the limit on the density of information transmitted through the optical fiber is not reached;

- Very small (compared to other fluids) attenuation of the light signal in the optical fiber. The best examples of Russian fibers have attenuation of 0.22 dB / km at a wavelength of 1.55 microns, which allows you to build a link length of up to 100 kilometers without regeneration of signals. For comparison, the best Sumitomo fiber at a wavelength of 1.55 microns has attenuation 0.154 dB / km. In US optical laboratories developed more 'transparent', so-called optical fluorozirconate fiber having a theoretical limit of about 0.02 dB / km at a wavelength of 2.5 microns. Laboratory studies have shown that on the basis of these fibers can be created a communication link with regeneration through portions 4600 km at a transmission order of 1 Gbit / s speed;

- OM made of quartz, which is based on silica, widely distributed, and inexpensive material because, unlike copper;

- Optical fibers have a diameter of about 100 microns, that is very compact and lightweight, which makes them promising for use as aviation, instrumentation, in cable technology;

- Since the optical fibers are insulators, therefore, the construction of communications systems is automatically achieved by isolation segments. In the optical system are completely electrically isolated from each other, and many of the problems associated with the earth and lifting capacities, which still occurred when connecting electrical cables, become irrelevant. Applying extra strong plastic for cable factories made self-supporting overhead cables that do not contain metal and thus safe in electrical terms. Such cables can be mounted on the masts of the existing power lines, both separately and integrated in the phase wire, saving significant funds for laying cable across rivers and other obstacles;

- Communications systems based on optical fibers are resistant to electromagnetic interference, and the information is transmitted over optical fibers is protected from unauthorized access. Fiber-optic communication lines can not listen in a non-destructive way. Any impact on the OB can be detected by monitoring (continuous monitoring) line integrity;

- An important property of optical fiber - longevity. Fiber life time, that is, preservation of its properties within certain limits, more than 25 years that allows to lay an optical fiber cable and one time, as needed, to increase channel capacity by replacing receivers and transmitters at a high-speed.

But there are also some disadvantages of fiber optic technology:

- When creating link requires highly active elements which convert electrical signals into light, and a light to electrical signals. To connect with OM transceiver equipment used optical connectors (connectors), which should have low optical losses and a great resource for connection-disconnection. Errors in the manufacture of such link elements must be of the order of a micron, i.e. meet the emission wavelength. Therefore, optical communication lines the production of these components is very expensive;

- Another drawback is that the precision required, and therefore expensive, process equipment for the installation of optical fibers.

Consequently, when an accident (breakage) of the optical cable, the cost of higher recovery than with copper cables.

The advantages of the use of fiber-optic communication lines (FOCL) are so significant that in spite of these shortcomings of the optical fiber, the communication lines are increasingly being used to transmit information.

2.1.2 Structural features FOC

One of the most important components of fiber optic is a fiber-optic cable (FOC). The defining parameters in the production of the FOC are the operating conditions and the capacity of the link.

Under the terms of operation of the cables are divided into: installation, station, zonal, long-distance.

The first two types of cables are designed for installation inside buildings and structures. They are compact, lightweight and usually have a small construction length.

Cables for the last two types are designed for installation in the wells of cable communications in the ground, on poles along the transmission line under water. These cables are protected from external influences and the construction length of over two kilometers.

The above features and requirements determine the design and type of optical cables. Currently, conventionally there are four types of structures OC (arbitrarily because in arrangement of optical fiber and for other purposes, they can be divided into a larger number of types and designs) [14, 15]:

a) concentric layer cable;

b) beam lay cables;

c) cables with the relevant carrier cores;

g) ribbon cables.

Figure 2.1 shows sketches of optical cable cross-sections of different types: type 'a' and 'b' refer to the classic design, the types of 'c' and 'd' characteristic of most optical cables.

1 - optical fiber; 2 - modules; 3-plastic tube; 4-power element.

a - concentric layer; b - twist beam; c - a core profile; d - belt

Figure 2.1 - Typical optical cable construction

OC 'a' is in the form of coils of optical modules, twisted around the central reinforcing element. Such a construction is effective when the number of the optical modules is not more than 20. Typical concentric layer OC has an outer diameter of 12 mm and 6 to 8 optical modules. The optical module is a polymeric tube with a freely laid fiber in it.

Optical type 'b' of the cable is made up of bundles of optical modules, concentric around a central reinforcing core. The beam is a polymeric tube, inside which there are profiled with longitudinal grooves cores. In these grooves the optical fibers are loosely housed. Unlike OС twisting concentric layer, helix in the optical cable module type 'b' have the same direction and pitch. This type of cable contains 25-50 modules in standard design - 40. The external diameter is 15 ... 25 mm.

Optical cable type 'c' consists of a core, which is a plastic bearing element with helical grooves into which freely without tension, with the primary fibers are laid containment or optical modules with a diameter smaller groove width. Core optical fibers or modules of insulating tape is wound and covered with a sheath. In some designs OC reinforcing core has a circular cross section around which a spiral wound gasket with alternating there between lie freely optical modules. The cables 'in' type typically contains 8-10 fibers. Their outer diameter - 20 mm.

Сore type cables 'd' is assembled from individual flat ribbons with parallel at a distance from each other in a few tenths of a millimeter waveguides. Twisted ribbon cable form the core. The reinforcing elements are located in a sheathed OC. Due to the dense packing of the cable of this design can be manufactured with a very small diameter. Thus, cable 144 of the optical fibers has an outer diameter of 12 mm. The small core sizes allow for layout in combination with other elements of the cable

Each of the considered OC types has its own advantages and disadvantages. Their use in each case is dictated by the installation conditions, the operation and the nature of the problem being solved.

To provide high bandwidth communication line produced FOC containing a small number (8) of single mode fiber with low attenuation, and cables for distribution networks may comprise up to 144 filaments as a single-mode and multi-mode, depending on the distances between network segments [12] .

2.1.3 Distribution of light beams in optical fibers

Optical fiber (Figure 2.1) consists of a core, in which the propagation of light waves, and a cover designed, on the one hand, to create the best conditions for reflection at the interface 'core - shell', and the other - to reduce the radiation energy in the surrounding space. In order to enhance the strength and thus the reliability of the fiber over the shell, usually superimposed reinforcing protective coating.

Figure 2.1 - General view of the model RH

This design is used in most RH optical cable (OC) as the underlying core is made from optically denser material. Optical fibers are characterized by a core diameter and the cladding and core refractive index profile, i.e. the dependence of the refractive index of the distance from the axis OB (Figure 2.3) [13].

All optical fibers are divided into two main groups: multimode MMF (multi mode fiber) and singlemode SMF (single mode fiber). In multimode OB having a light-carrying core diameter on the order more transmission wavelengths, distributed a number of different types of light rays - mod. Multimode fibers are separated by the profile of the refractive index in the step (step index multi mode fiber) and gradient (graded index multi mode fiber).

The main factors affecting the nature of light propagation in the fiber, along with the emission wavelength, are the geometric parameters of fiber, attenuation, dispersion.

The principle of the propagation of optical radiation along the optical fiber based on the phenomenon of total internal reflection at the interface with

different refractive indices. The propagation of light beams in an optically denser medium surrounded by a less dense shown in Figure 2.2. The angle of total internal reflection, in which the incident on the border of the optically denser and an optically less dense medium is totally reflected light is determined by the relation

(2.1)

where n1 - the refractive index of the core RH; n2 - refractive index of the shell RH, and n1> n2.

Figure 2.2 - Distribution of radiation and by stepwise gradient multimode and singlemode OС

If you get on the end of the light emission RH it can spread three types of light beams, called guides and attendant emitted rays, the existence and prevalence of any type of rays determined by the angle of incidence on the interface between the 'core - shell'. Those rays which fall on the interface at an angle (rays 1, 2 and 3), and are reflected from it again back into the fiber core, and propagates in it without undergoing refraction. Since the path of the rays is completely located within the propagation medium - core fiber, they are spread over long distances and are called rails.

Rays incident on the interface at an angle (rays 4), are called flowing rays (rays of the shell). Reaching the boundaries of the 'core - shell', these rays are reflected and refracted, each time losing sheathed fiber portion of the energy, and therefore disappear completely at some distance from the fiber end. The rays that are emitted from the shell to the surrounding space (5-rays) emitted rays are named and appear in places of irregularities or curling due RH. Radiated and the resulting beams are parasitic and cause dissipation of energy and the distortion of the information signal.

2.1.4 Modes propagating in optical waveguides

In general, the propagation of electromagnetic waves described by the system of Maxwell's equations in differential form:

(2.2)

Where - density of electric charge; and - the electric and magnetic fields, respectively; - Current density; and - the electric and magnetic induction.

If we imagine the electric and magnetic fields, and with the help of the Fourier transform [14]:

(2.3)

The wave equations take the form:

(2.4)

Where - Laplace operator.

The light guide can be represented with a perfect cylinder z, the longitudinal axis of the x-axis and in the transverse (xy) plane form a horizontal (xz) and vertical (xz) plane. In this system, there are four classes of waves (E and H orthogonal):

- Transverse T: Ez = Hz oriented = 0; E = Ey; H = Hx;

- Electric E: Ez = 0 Hz oriented = 0; E = (Ey, Ez) - distributed in the plane (yz); H = Hx;

- Magnetic H: = 0 Hz oriented, Ez = 0; H = (Hx, Hz oriented) - distributed in the plane (xz), E = Ez;

- EN mixed or not: Ez = 0 Hz oriented = 0; E = (Ey, Ez), H = (Hx, Hz oriented) - distributed in the plane (the xz) and (yz).

ancoordinates (z, r, ц), while a solution is sought in the form of waves with components Ez, Hz oriented type:

, (2.5)

Where and - normalizing constant; - The desired function; - Longitudinal wave propagation coefficient.

Solutions are obtained in the form of sets of m (there are whole index m) of ordinary Bessel functions for the core and modified Hankel functions for the shell, and where and - lateral spread of ratios in the core and the shell, respectively, - the wave number. The parameter is defined as the solution of the characteristic equation obtained from the boundary conditions requiring continuity of the tangential component Ez and Hz oriented electromagnetic field on the boundary of the core and the shell section. The characteristic equation, in turn, provides a set of solutions of n (integer indices appear n) for each integer m, i.e. we have their own values, each of which corresponds to a certain type of wave called fashion. The result is a set of events, which is based too much on the use of double indices.

The condition for the existence of a guided mode is the exponential decay of its fields in the shell along the coordinate r, which is determined by the cross-propagation coefficient in the shell. When = 0 is set critical mode, which consists in the impossibility of existence of the guided mode, which corresponds to [14]:

(2.6)

This equation has an infinite number of solutions [14]:

(2.7)

We introduce the quantity called the normalized frequency V, which links the structural parameters of the agents and the wavelength of light, and determined by the following expression:

(2.8)

When = 0 for each of the solutions of equation (2.6) there is a critical value of the normalized frequency (m = 1, 2, 3, ..., n = 0, 1, 2, 3 ...):

etc.

For HE₁₁ mode critical normalized frequency. This fashion spread at any frequency, and structural parameters of the fiber and is a fundamental step fashion agents. Choosing options OM can be achieved only mode of propagation of this mode, which is subject to:

(2.9)

The minimum wavelength at which propagates in the fundamental mode OM, called Fiber cutoff wavelength. The value is determined from the last expression as:

(2.10)

2.1.5 Single-mode optical fiber

Single-mode fiber are subdivided into staggered single-mode fiber (step index single mode fiber) or standard fiber SF (standard fiber), to fiber dispersion shifted DSF (dispersion-shifted single mode fiber), and fibers with a non-zero dispersion-shifted NZDSF (non-zero dispersion-shifted single mode fiber).

In stepped a single-mode optical fiber (SF) (Figure 2.3) the diameter of the light-carrying core is 8-10 microns and is comparable to the wavelength of light. In such a fiber at a sufficiently high light wavelength л> лCF (лCF - cutoff wavelength) covers only one ray (single mode). The single-mode optical fiber mode is realized in the transparent windows 1310 nm and 1550 nm. Spread only one mode eliminates modal dispersion and provides a very high bandwidth single-mode fiber in these windows transparency. The best mode of propagation viewpoint of dispersion is achieved in the vicinity of wavelength 1310 nm, when the chromatic dispersion becomes zero. From the point of view of the losses is not the best transparency of the window. In this window, the loss is 0.3 - 0.4 dB / km, while the smallest attenuation of 0.20 - 0.25 dB / km is achieved in the 1550 nm window.

Figure 2.3 - Profiles of the refractive index

The single-mode optical fiber, dispersion-shifted (DSF) (Figure 2.3), the wavelength at which the dispersion becomes zero - zero dispersion wavelength л0 - biased transparency window of 1550 nm. This shift is achieved thanks to the special profile of the refractive index of the fiber. Thus, in the dispersion-shifted fiber with the best performance are realized both in minimum dispersion, and the loss at a minimum. Therefore, such a fiber is better suited for the construction of long segments with a distance between repeaters to 100 km or more. Of course, only the working wavelength is taken close to 1550 nm.

A single mode optical fiber having non-zero offset NZDSF dispersion unlike DSF optimized for transmission than a single wavelength and multiple wavelength (multiplex waveform), and most effectively be used in the construction of highways 'all-optical networks' - networks to nodes which are not optoelectronic conversion takes place in the propagation of the optical signal.

Optimization of these three types of single-mode OB does not mean that they should always be used exclusively for specific tasks: SF - signal transmission at a wavelength of 1310 nm, the DSF - signal transmission at a wavelength of 1550 nm, NZDSF - multiplex signal transmission in the window 1530-1560 nm. For example, multiplexed signal in 1530-1560 nm window can be transmitted stepwise and standard single mode fiber SF [6]. However, the length of hop without using SF fiber will be less than using NZDSF, or otherwise require a very narrow spectral emission band laser transmitters in order to reduce the resultant chromatic dispersion. The maximum allowable distance is determined by the specification of both the fiber (attenuation, dispersion), and transceiver equipment (power, frequency, spectral broadening of the transmitter radiation, receiver sensitivity).

The most widely used fiber-optic fibers following standards:

- Multimode gradient fiber 50/125;

- Multimode gradient fiber 62.5 / 125;

- Single-mode fiber is a step SF (fiber unbiased variance or standard fiber) 8-10 / 125;

- A single-mode dispersion shifted fiber DSF 8-10 / 125;

- Single-mode fiber with a non-zero dispersion-shifted NZDSF (the profile of the refractive index of the fiber is similar to the previous type of fiber).

2.1.6 Constant distribution and phase velocity

The wave number k can be viewed as a vector whose direction coincides with the direction of light propagation in bulk media. This vector is called the wave vector. In a medium with a refractive index equal to the magnitude of the wave vector. In the case of light propagation inside the waveguide light propagation direction coincides with the direction в of the projection of the wave vector k, on the axis of the waveguide:

(2.11)

Where - the angle complementary to the angle of 90 i (or the angle between the beam and the axis as shown in Figure 2.4); в - it called constant propagation and plays the same role as the waveguide in the wave number k in free space so as , in accordance with the formula 2.11, i and wavelength dependent [16].

Figure 2.4 - The wave vector and the constant spread

The angle of incidence varies between and р / 2. Consequently:

(2.12)

Thus, the magnitude of propagation constant inside the waveguide always lies between the values of wave number plane light waves in the material of the core and cladding. If we consider that it is possible to rewrite this relation in terms of the phase velocity:

(2.13)

The phase velocity of propagation modes concluded between the phase velocity of the waves in the two bulk materials.

The speed of propagation of the light signal or the group velocity - is the speed of propagation of the light pulse envelope. In general, the group velocity u is not equal to the phase velocity. The difference of the phase velocities of modes leads to distortion of the input light beam as it propagates along the fiber.

The fiber with a parabolic refractive index gradient oblique rays propagate along a curved trajectory which is naturally longer than the propagation path of the axial ray. However, because of the refractive index decreasing with distance from the axis of the fiber, the velocity of propagation of the light signal components when approaching the optical fiber cladding increases, so that the resulting propagation time constituting at RH is approximately the same. Thus, the variance or change in the propagation time of the different modes are minimized, and the width of the fiber bandwidth increases. Exact calculation shows that the difference in group velocities of the various modes in such a fiber is substantially less than in the fiber with a step refractive index profile. Optical fiber that can support the spread of only the lowest-order mode, called single-mode.

Thus, each mode propagating in OM, characterized by constant along the fiber length distribution of intensity in the cross section of the propagation constant в, and v of the phase and group velocities u propagation along the optical axis, which are different for different modes. Due to the difference of phase velocities of the modes of the wave front and the field distribution in the cross-sectional change along the fiber axis. Due to different modes of group velocities of light pulses widen, and a phenomenon called modal dispersion.

The single-mode fiber there exists only one mode of propagation, so such fiber is characterized by a constant field distribution in the cross section, it does not intermode dispersion, and it can transmit radiation with a very broad modulation bandwidth limited only other kinds of dispersion [13].

2.1.7 Calculation of the main characteristics of the fiber optic link

OC Quality checked using conventional measurement methods. If you have a single-mode Sun bends or connections, the mode field diameter size is an important factor influencing the damping characteristics. Thus, increasing the mode field diameter leads to deterioration of light transmittance in the bends, but reduces the loss of detachable and non-detachable joints [17].

Calculation of the numerical aperture of the optical fiber. The most important parameter of the generalized optical fiber is the aperture.

The numerical aperture - the angle between the optical axis and forming a cone of light entering the optical fiber end, wherein the condition of total internal reflection.

We calculate the index of refraction n2 shell. Based on optical characteristics of the cable numerical aperture NA = 0,11.

It is known that:

, (2.14)

Where n1 - according to the formula 2.1 core refractive index equal to 1.4681, then

n₂=, (2.15)

n₂=

The calculation of the normalized frequency. The most important parameter of the generalized optical fiber used for the evaluation of its properties, is the normalized frequency V (Formula 2.8).

In practice, this option is determined by the expression:

V = , (2.16)

where a - core shell radius a = 4.5 m; n1 - the refractive index of the core, n1 = 1,4681; n2 - (according to 2.15), the clad refractive index, n2 = 1,4639, then

V = = 2,3741

The calculation of the cable parameters, based on the fact that we have a single-mode fiber with a step refractive index profile with a core diameter 2a = 9mkm and critical wavelength = 1250 nm, the mode diameter 2₀ field at a wavelength of 1310 nm [14]:

2₀ 2a, (2.17)

Where - working wavelength, = 1310 nm; с - critical wavelength above which the fiber is sent to only the fundamental mode, с = 1250 nm; Vc - normalized critical frequency for single-mode Vc = 2,405.

2₀ 9 = 10,196, mcm.

This means that it is possible to select OF core with a diameter of 10 microns. Given that the fiber boundary between two media core - shell are transparent glass, perhaps not only a reflection of the optical beam, and its penetration into the skin. To prevent the transition energy to the shell and radiation into the environment must observe the condition of total internal reflection and aperture [16,17].

It is known that the transition from a medium with a higher density in the environment with lower density, that is, when n1> n2, wave at a certain angle of incidence is totally reflected and passes into another medium. The angle of incidence at which all of the energy is reflected from the boundary between two media, while wp =_v in, is called the angle of total internal reflection:

, (2.18)

Where m and h -, respectively, and the dielectric core magnetic permeability (m1, e1) and shell (m2, e2).

When wp <_v in the refracted beam passes along the boundary between 'core - shell' and not emitted into the surrounding space.

When wp>_v in the energy received by the core is completely reflected and propagates through the optical fiber. The greater the angle of incidence, wp>_v in the range of up to 90 degrees in the better propagation conditions and the faster the wave comes to the receiving end. In this case, all energy is concentrated in the fiber core and substantially no emitted into the environment. When the beam angle of incidence smaller than the angle of total reflection, wp_v <a, the energy penetrates the membrane, is emitted into the external space through the optical fiber transmission and inefficient.

Total internal reflection mode determines the supply condition of the light on the front end of the optical fiber. Fiber optic transmits only light enclosed within a solid angle _v, the value of which is due to the angle of total internal reflection in_v. This solid angle_v characterized by a numerical aperture.

Between the angles of total internal reflection _v in the beam aperture angle _v and fall and there is a correlation. The greater the angle _v, the smaller the aperture _v of a fiber. It seeks to ensure that the angle of incidence on the boundary core - shell wp was greater than the angle _v of total internal reflection in and ranged from _v to 90 degrees and the angle of the input beam to the end face of the fiber w fit into the aperture angle_a (w <a) .

We find critical с angle at which the condition of total internal reflection:

с= (2.19)

с=

Knowing the indicators of refraction n2 shell and core n1 calculate the relative refractive index difference :

(2.20)

The calculation of the length of the regeneration area. The calculation of the length of the regeneration area () is an important section of the design. To provide a better quality of information transfer and saving of costs is preferable that a maximum. The amount is determined mainly by two factors: the loss and dispersion in the optical cable. The most promising in this respect are systems with single-mode fiber (AF) and a wavelength of 1.3. . .1,55 That for small losses it possible to obtain a high information capacity. Determination of length FOL regenerator section is based on a predetermined communication quality parameters and line capacity after the selected transmission system and a typical optical cable. The quality of communication in the digital transmission systems in the first approximation, determined by the level of fluctuating noise at the input of the photodetector and inter-symbol interference, that is, pulses overlap with their broadening. With increasing length of the line broadening of the pulses, characterized magnitude, increases, the probability of error increases. Thus, the length of the regeneration area limited either attenuation or pulse broadening in line.

For undistorted receiving PCM signals sufficient to fulfill the requirement:

(2.21)

Where - the duration of the clock period PCM signal; - pulse duration; - the resultant dispersion or:

(2.22)

Where - the clock frequency of the signal line.

If the pause is sending duration, then:

(2.23)

The pulse broadening waveguide past one section does not exceed half the length of the clock interval. These conditions determine the first estimated the ratio to determine the permissible length of the regeneration of the area:

- , (2.24)

or:

(2.25)

Where - the resultant dispersion, as selected single-mode cable, the mode dispersion not consider. In singlemode optical fibers the resultant value is defined chromatic dispersion of the dispersion:

(2.26)

Where () - material dispersion; () - Wave dispersion.

Material dispersion () - the material dependence of the refractive index on the wavelength. With increasing wavelength dispersion coefficient decreases:

(2.27)

Where - the width of the spectral line of the radiation source, which is equal to 0,14 laser (for technical data on our equipment = 1,8); M () - specific material dispersion of silica glass is -20.

=,

The wave dispersion () - dependence of the propagation coefficient of the wavelength:

(2.28)

Where B () - Specific wave dispersion for quartz glass is 10

= ,

Summarizing the material and waveguide dispersion, chromatic or obtain the resulting dispersion:

(2.29)

,

This value is close to the technical data of the equipment and cables.

We find the permissible length of the regeneration of the area:

The second calculated ratio can be obtained by considering that the useful signal power at the input of the detector should not be less than the specified minimum permissible power , which provides a necessary reliability of signal transmission:

Where - the power level of the radiation generator; ; - loss of detachable connections (used to connect the receiver and the transmitter to the UK); , - losses at the input and output of radiation from fiber; ; - loss of permanent connections; ; - attenuation of the optical fiber; ; - construction length OC.

The value is the name of the power equipment capacity and depends on the type of the selected light source and a photodetector:

(2.31)

The energy potential of taking passport data of the selected equipment. It is equal to = 31 .

The length of the maximum regeneration area defined by lines of weakening can be obtained from the relationship:

(2.32)

Where - the average value plus 6;- 0.5; ,- 1,0;

- 0.1; - 0.22; - 4 km ; - (-36) (For the type of photo detector); m- System supply FOTS attenuation in the regeneration area.

System margin takes into account changes in the composition of the optical cable due to the appearance of additional (repair) of inserts, welded joints, as well as changes caused by environmental exposure to optical cable characteristics of the environment and the deterioration of optical connectors, quality for life, and is set in the design FOTS on the basis of its destination operating conditions and service provider, in particular based on statistical damage (breaks) in the cable operator's service area. Recommended range of values ??set by the system reserve of 2 (the most favorable operating conditions) to 6 (worst-case operating conditions). These data are taken from the data sheet for the equipment [25].

Specifies the maximum length of the regeneration section, according to the formula (2.32):

Therefore, for single-mode fiber length depends on the regeneration site attenuation, but the calculation is performed with some margin, so more than in the technical specifications of the equipment manufacturer, which may be because the span calculation. It may not have been taken into account some parameters changed by the manufacturer in the design and manufacturing techniques that may be a trade secret, the use of cable with less attenuation.

Length between OP-1 (Stepnogorsk) and OP-2 (KOCshetau) is 251, which exceeds the maximum = 98.4, therefore, must be installed on the cable line URP (SRP).

Therefore, you must choose a location point of the regeneration that it satisfies the requirements of regeneration, and preferably located in the village, to ensure a constant supply of stationary equipment. In this case, it takes two regeneration points, to fit such requirements pos. Saule and g.Schuchinsk.

2.2 Digital transmission systems

2.2.1 The concept of building a modern transmission systems

The development of science and the acceleration of technological progress is not possible without improving communications, data collection, transmission and processing of information.

Intensive development of new information technologies in recent years has led to the rapid development of microprocessor technology, which stimulated the development of digital transmission techniques.

Ultimately, this led to the creation of new high-speed WAN technologies: PDH, SONET, SDH, ISDN, Frame Relay and ATM.

One of the most advanced technology currently used for the construction of communication networks is the technology SDH synchronous digital hierarchy.

Interest in the SDH due to the fact that this technology has replaced the PCM pulse code modulation (PCM) and plesiochronous digital hierarchy of PDH (PDH).

Began actively implemented as a result of the mass installation of modern foreign digital PBX, allowing to operate with flows of 2 Mbit / s, and the creation of local regional SDH rings.

Synchronous Digital Hierarchy (SDH) has significant advantages over previous generations of systems, it allows you to fully realize the potential of fiber-optic transmission lines and create flexible, easy to operate and control the network, ensuring high-quality communications.

Thus, SDH concept allows optimally combine processes high-quality digital data transmission with automated management processes, control and network services in a single system.

SDH systems provide transmission speeds of 155 Mbit / s and above, and can be transported as digital signals of existing systems (eg, common on city network of PCM-30), as well as promising new services, including broadband.

SDH equipment is software-controlled and integrates the means of conversion, transmission, operational switching, control, control.

With the advent of modern fiber-optic cables (FOC) made possible a high transmission rate in linear tract (RT) digital transmission systems with a simultaneous lengthening of the regeneration sections up to 100 km or more.

Performance of LT exceeds the performance of digital paths in the cables with metal vapors 100 times or more that dramatically increases their cost-effectiveness.

Most repeaters it is possible to combine with the terminal or transit stations. From this it follows that the SDH - is not just a new transmission system, this fundamental change in network architecture management. The introduction of SDH is a qualitatively new stage in the development of digital communication network.

Therefore, the program of development of Kazakhstan in the long term the introduction of new information technologies belongs to one of the priority seats. Construction of fiber optic links in this area - the next logical step in the comprehensive modernization of communication of Kazakhstan, which will result in the creation of a powerful modern information network.

Advantages of fiber optic to copper lines are clear: high reliability and noise immunity, large data transmission speed, large bandwidth. FOTS raises means of telecommunications to a new, much higher level of development.

This reliable telephone service, Internet access and other global projects, the implementation of which is currently virtually impossible at this site. Introduction FOTS raise to a higher level and a secondary communication network, with a significant extension of new services which require broadband connections (e.g., network communication technology - video, video conferencing, industrial television, computer networks, operating in real time).

The planned fiber-optic route is intended primarily to provide customers high-quality communications. Advantages of fiber optic to copper lines are clear: high reliability and noise immunity, large data transmission speed, large bandwidth. FOTS raises means of telecommunications to a new, much higher level of development.

This reliable telephone service, Internet access and other global projects, the implementation of which is currently virtually impossible at this site. Introduction FOTS raise to a higher level and a secondary communication network, with a significant extension of new services which require broadband connections (e.g., network communication technology - video, video conferencing, industrial television, computer networks, operating in real time).

The planned fiber-optic route is intended primarily to provide customers high-quality communications.

2.2.2 Transmission systems of PDH, characteristic features

In modern networks are operated as a plesiochronous system and synchronous digital hierarchy systems.

Standard PDH - plesiochronous digital hierarchy. Hierarchy recommended for digital transmission systems, something like a calendar hierarchy. For this purpose it was necessary to select a certain unit of measure 'e' bit rate common to all countries and companies that produce equipment of transmission systems and allows you to measure the speed of the total digital streams. This 'unit' rate worldwide is digital speech transmission rate of 64 kbit / c. Channel on which are transmitted at 64,000 bits / s, is called the primary digital channel. Possibilities any digital transmission system estimates the number of organized with the help of just such standard channels.

Combining flows leveling speed has been called plesiochronous (nearly synchronous), and the existing hierarchy of speeds transmission of digital streams, and hence the type of PCM transmission systems (PCM) - plesiochronous digital hierarchy (in the English writing Plesiohronous Digital Hierarhi, PDH).

Plesiochronous digital hierarchy was developed in the early 80s. In the hierarchy of great hopes, but it was not very flexible in order to enter into the digital stream 'rushing' at a high speed or low-speed output from it flows must be fully 'embroider', and then 'sew' high flow. This requires installation of a large number of multiplexers and de multiplexers. It is clear that to do this operation is often quite expensive.

The system uses the principle of PDH plesiochronous multiplexing, according to which for multiplexing, for example, the 4-E1 (2048 kbit / s) into one stream E2 (8448 kbit / s) alignment procedure is performed such frequency signals occurring by stuffing. As a result, when multiplexing is necessary to make a step by step process of restoration of the original channels. For example, in the secondary digital telephone networks the most common use of E1. When sending this stream for PDH networks tract E3 must first perform incremental multiplexing E1-E2-E3-step demultiplexing and then E2-E3-E1 at each point E1 channel allocation. This is a major drawback PDH equipment - due to the increase in the number of necessary equipment for the separation of one or two streams. E1 primary digital channel DSO combines 32 channels, of which one DSO used for frame synchronization, another - for signaling. Still this stream consists of 32 time slots of 8 bits each. Frame repetition frequency 8 kHz, which gives the flow rate of 32 * 8 * 8 = 2048 kbit / s.

The essence of the main drawbacks RDN is that the addition of equalizing bit makes it impossible to identify and output, for example, stream 64 Mbit / sec or 2 Mbit / s 'hardwired' into the stream of 140 Mbit / s without complete demultiplexing or 'embroidered' of this stream and removing leveling bit. One thing to 'drive' the flow of long-distance or international calls from one call center to another 'mixing' and 'bark' them quite rare.

Another thing - to connect several banks and / or their separation via PDH network. In the latter case often have to either output stream 64 kbit / s and 2 Mbit / s from the flow of 140 Mbit / s to make it, for example, a bank branch, or vice versa to output a stream of 64 kbit / s and 2 Mbit / s from the bank for putting it back into the flow of 140 Mbps, the implementation of such a step input conclusion have to spend quite a complex operation the three-level demultiplexing ( 'bark') PDH signal removing adding leveling bit (all three levels) and his subsequent three-level multiplexing ( 'stitching') adding new leveling bits. the alarm. However, these tools are too weak.

If you have many users that require input output source (of 2 Mbit s) for the instrumental implementation of network flows require an excessively large number of multiplexers, as a result of operation of the network becomes economically advantageous.

Another bottleneck technology PDH - weak capacity in the organization of channels for purposes of control and flow control in the network and the almost complete absence of routing funds grassroots multiplexed streams, which is essential for use in data networks. Typically, for the purposes of identification and subsequent signaling flow is divided into groups of time slots or frames, which are then assembled in groups of several frames or multiframe. The latter, allowing the identification of the receiving side of the individual frames are supplied with additional bits of cyclic error-correcting codes and used PDH frames and multiframes increases (with an increase in the number of multiplexing and switching streams for routing), the possibility of error in tracking the 'history' of current switching, and hence increases and the possibility of 'losing' information not only about the current switching, but also about his 'history' in general, which leads to disruption of routing all traffic scheme. So it would seem essential advantage of the method - a small 'congestion headings' (Recommendation G.704 does not provide for the necessary for normal routing headers) - in fact, turns into another serious shortcoming as soon as there is a need for advanced routing, network PDH caused by the use of data .

And so, a number of shortcomings PDH:

-hard input / output digital streams at intermediate points;

-no funds network of automatic monitoring and control;

-multistage restore the presence of three different hierarchies.

2.2.3 SDH Standard

These shortcomings RDN and a number of other factors led to the development in the United States is still one of the hierarchy - the hierarchy of SONET synchronous optical network, and in Europe Analytical SDH synchronous digital hierarchy, proposed for use in the fiber optic link. But due to unfortunate selected baud rate for STS-1, the decision was made - to abandon the creation of the SONET, and to create an it-based SONET / SDH at a rate of 51.84 Mbit / s of the first level of the SDH OC1. As a result, the NEO SONET / SDH STM-1 corresponds to the SDH hierarchy. Transmission speed SDH hierarchy presented in Table 3.1.

Table 3.1 - SDH hierarchy bit rates

SDH - Synchronous Digital Hierarchy. SDH - is a set of digital structures, standardized for the purpose of transporting it necessary to adapt the load on the physical network. SDH - calculated as a transport signal existing PDH, with the speed specified in recommendation G.703 as the signals of new broadband services. At the same time significantly increase the reliability and survivability of networks, their flexibility, quality of communication, Linear SDH signals are arranged in a so-called synchronous transport modules STM. The first of these STM - 1 corresponds to the speed of 155 Mbit / s. Each subsequent rate is four times greater than the previous one and formed by a synchronous byte multiplexing. Already standardized STM - 4 (622 Mbit / s) and STM - 16 (2.5 Gbit / s).

In the SDH network using the principle of container traffic to be pre-arranged transportation of signals in standard containers C. All operations are performed with the containers, regardless of their content. This ensures the transparency of the SDH network, it is possible to transport a variety of SDH signals, streams of ATM cells, or any new signals. There are four levels of containers. All of them, together with SDH signals placed in them are listed in Table 3.

Table 3.2- SDH containers four levels

An important feature of SDH network is to divide it into three functional layers, which are subdivided into sublayers (Table 3.3). Each layer maintains the overlying layer and has a certain access point. Layers have their own control and management tools, simplifies operation on liquidation of consequences of failures and reduce their impact on the overlying layer. The independence of the layers enables you to implement, upgrade or replace them without affecting other layers.

Table 3.3 - SDH division into functional layers

The most important for the following discussion are network layers: channels, paths and sections, a network of canals - a layer that serves the user's own. These terminals are connected to the sets of SDH terminal equipment trunks. channel network connects different sets SDH terminal equipment through the switching station.

Channel groups are combined in different orders group paths, forming a network of paths. There are two paths of network layers (from top to bottom over SDH hierarchy) of the lower and higher order. The layer paths provide software and remote monitoring and control connections. All the paths end at operational switching equipment, part of the SDH multiplexers.

Group paths are organized in line, the construction of which depends on the transmission medium (OM, RRL). This network transmission layer. It is divided into two parts: a layer sections (upper) layer and a physical medium. The network layer is divided into two sections. The top layer is a multiplex section (MS). MS - provides transfer of information between the points where terminate or switch paths. The bottom layer of regeneration section (RS) - provides the transfer of information between the regenerators and the end points or switching paths. New digital hierarchy was conceived as a high-speed.

Application of SDH-technology:

- Transportation of data streams in the ATM networks. This SDH equipment transmits the signal over long distances, carries ATM Cross Connect - streams and allows you to organize the ATM network with complex topology, even for a linear arrangement of ATM switches;

- The transfer of a large number of E1. Primary E1 digital circuit 32 combines the channel DCO (main digital channel), one of which is used to DCO frame synchronization, another - for signaling. This stream frame consists of 32 time slots of 8 bits each. Frame repetition frequency 8 kHz, which gives the flow rate of 32 x 8 x 8 = 2048 kbit / s.

- Creation of fail-safe transport networks with a fast recovery time performance (on this indicator SDH significantly superior to other technologies).

With the spread of SDH - technology, when combined networks of various operators sharply there is a problem of global synchronization of nodes, and this point should not be underestimated.

The trend of recent years - the replacement of currently existing PDH SDH networking systems, as well as the use of not only the operators of technology, but also for the construction of highways corporate information systems.

3. Working documents

3.1 Proposals for the selection of equipment for communication

communication lines channel

3.1.1 The main function module SDH networks

The main function module is a multiplexer SDH networks. The term itself is used as a multiplexer for the multiplexers that are used to build (multiplexing) a high speed flow of the low-speed and disassembly (demultiplexing) the high-flow in order to separate low-speed streams.

SDH multiplexers in contrast to conventional multiplexers are used, for example, in the PDH network, as a function properly operate the multiplexer and the terminal access function devices, allowing low-speed channels PDH connect directly to their input ports. They are more versatile and flexible devices that perform tasks other than multiplexing and switching problems still, concentration and regeneration. Accepted, however, to distinguish two main types of multiplexer: terminal multiplexer and the multiplexer input - output.

Terminal Multiplexer (TM) is a multiplexer and terminal SDH network with the access channels, the appropriate tribes PDH and SDH. TM can be administered or channels, that is, switch them with tribnogo interface input to line input or output channels, that is, switch them with a linear input to output tribnogo interface. Typically, this is limited to switching tribes 1,5 and 2 Mbit / s.

Another important feature of the multiplexer is the presence of two optical line outputs (reception / transmission channels), called aggregate outputs and used to create one hundred percent redundancy mode, or the protection of 1 + 1 in order to increase reliability.

The multiplexer input / output (ADM) has the same inlet tribo set as a terminal multiplexer. It allows you to enter and display the corresponding channels. In addition to switching capabilities provided by TM, the ADM allows a through switching output streams in both directions, as well as to the closure of the channel on the receiving channel on both sides in the case of failure of one of the directions. Finally, it allows (in case of accidental failure of the multiplexer) to skip the main optical flow by themselves in the bypass mode.

Consider options for the acquisition of synchronous multiplexers: SDM-1 (ECI Telecom, Israel), SMA-1 R2 (Siemens, Germany) and FOX-1640 (Alcatel, Germany). The comparison results are summarized in Table 1 [PV].

Currently, due to the high saturation of the market of telecommunications, equipment selection problem ceases to be purely technical and economic challenge and becomes a component of policy makers in relation to suppliers.

In this thesis project we propose to use the SDM-1 equipment company ECI Telecom (Israel), because this site is part of a single zone network route Stepnogorsk-KOCshetau.

Multiplexer SDM-1 consists of the following sections (Table 3.1):

Table 3.1-SDM-1 multiplexer Sections

Each SDM-1 is a unit located on the same shelf, which may contain from 21 to 63 component interfaces with a transmission speed of 2 Mbit / s, three - 34 Mbit / s, three - 45 Mbit / s, one - 140 Mbit / s or one - 155 Mbit / s (STM-1), and certain combinations of these interfaces. Since STM-1 standard allows a maximum of 155 Mbit / s aggregate line, the number of supported component interfaces (with protection) in a given moment of time is more limited: either 63 to 2 Mbit / s, three 34 Mbit / s, three 45 Mbit / with one 140 Mbit / s, a completely filled 155 Mbit / s, four partially filled with 155 Mbit / s, or some combination of these interfaces, in an amount not exceeding the STM-1 rate.

Using two modular line in an unprotected mode, you can increase the total number of supported component interfaces. In addition, SDM-1 provided more bandwidth can serve the purpose of dynamic allocation in response to changing traffic requirements.

Aggregate interfaces provide access to the lines connecting the mounting location of various SDM-1. The interface works with SDH data rate STM-1 (155.52 Mbit / s). When combined with a fiber-optic cables 1 from one another SDM SDM system 1 located in a remote location using optical aggregate interfaces. At shorter distances in this connection, instead you can use the optical electric aggregation channel.

Eight slots provided for component boards. Additional fees may give the opportunity to save on administrative costs because the network provider can place these or other additional fees in the system and enter them into operation as the demands from the traffic.

SDM-1 is monitored and controlled by the CPU, which communicates with the various parts of the system and the outside world. The system software is stored on the memory card that allows you to frequently and easily update the software by downloading from a remote source. Software communication management software is based on a seven-element model of OSI, working in a UNIX environment.

In normal operation, the system synchronizes to choose the source of synchronization. With this source connected a voltage controlled crystal oscillator, which generates an internal clock signal to SDM-1, and the time for SDH transmission line. This source can be an external timer signal, a component signal or SDH line signal. If synchronization sources are unavailable, SDM-1 is able to maintain standby mode with the stability of 4,6 ppm (parts per million).

SDM-1 is powered -48 or -60 VDC from the external battery system. The system's power structure implemented the principle of distributed architecture, ie, each card has its own built-in power supply. This achieves low cost and low power consumption in a partially filled SDM-1 configurations.

An important property of sequentially implemented in the system is its modularity. As already mentioned, all the component boards are completely interchangeable, and therefore can be installed in the same slots, regardless of the exchange rate supported by them.

SDM-1 architecture is similar to the architecture of the SDM-4 company ECI Telecom, which provides a family of products that are compatible with each other, and cost-effective in terms of maintenance and spare parts. Most boards are interchangeable with boards SDM-4, ??which makes it easy to modify the system.

Proposals on Timing of SDH network sources listed at the end of the explanatory note [PG].

3.1.2 Proposal for the selection of the radiation source and photodetector

There are two types of semiconductor light sources, light emitting diodes and lasers. For the fiber optic portion of Stepnogorsk KOCshetau, you need to select as a radiation source laser.

The laser has a high speed and a narrow spectrum width. From the family of semiconductor lasers is best to choose lasers with distributed feedback. These lasers operate in single-frequency mode, the emission spectrum width is less than 0.5 km. Temperature instability wavelength lasers with distributed feedback amounts to about OD km / k. The level of the output radiation, lasers powerful version highly varies within 3 to 6 dB m.

As the photodetectors in optical fiber communication systems using semiconductor p-i-n photodiodes and avalanche photodiodes. These devices are small and fairly well joined to optical fibers. The p-i-n photodiodes each absorbed photon creates a pair of 'electron-hole'. In avalanche photodiodes internal amplification of the signal occurs, since they are designed so that they formed a region with a strong electric field E (3 x 106 V / cm). In this field, the electrons generated by the light, are accelerated to energies sufficient to impact ionization of atoms of the crystal lattice. The resulting ionization of the free carriers is also accelerated and give birth to a new pair. This avalanche process leads to the fact that the absorption of a photon generates more than one electron-hole pair, and the tens and hundreds. Thus, by using a highly sensitive avalanche photodiodes as photodetectors version designed for fiber optic link, you can change the input level from - 39 to -17 dBm.

Using lasers with distributed feedback and avalanche photodiodes can get quite large regeneration areas that allow IUU fishing to place in the settlements. In Kazakhstan, the distance between the settlements can be up to 250 km. In this case, the power transmission system margin may be insufficient for covering this distance. In such cases it is possible to use optical amplifiers and preamplifiers.

The main equipment optical amplifying element is an optical waveguide fiber doped with erbium. Figure 1 shows a functional block diagram of an optical amplifier [PD].

Figure 2 is a functional diagram of an optical preamplifier. The input optical signal in a location with the pumping laser beam enters the optical fiber doped with erbium, wherein the light energy is redistributed between radiations [PD].

Further, through the optical isolator radiation enters the optical bandpass filter tuned to the operating wavelength, wherein the removal of parasitic modes occurs.

The input level varies from -45 dB to -15 m. In the case of using an optical preamplifier is used as a photodetector APD power standard. The output level changes from +12 to +15 dBm.

An optical preamplifier used in conjunction with an optical amplifier, while the optical amplifier can be used separately.

3.2 Welding questions, and measurement of the optical fiber connection

We have said that optical cables are manufactured certain dli¬ny called construction. Usually it does not exceed 4 ... 5 km (for transoceanic fiber optic - 50 km). optic line length in the overwhelming number of cases exceeds the building many times. Therefore optic cables laid in the sewer, the ground or hung on poles, you must so¬edinyat, t. E. To splice together. For this optical fiber end is freed from QA module length and 0.5 ... 1.0 m and interconnected 'to¬rets-end' by means of welding or gluing.

Above it was said that optical cables are made of a certain length, which is called building. Usually it does not exceed 4 ... 5 km (for transoceanic fiber optic - 50 km). optic line length in the overwhelming number of cases exceeds the building many times. Therefore optic cables laid in the sewer, the ground or hung on poles, must be connected, ie. E. To splice together. For this optical fiber end is freed from OC module length and 0.5 ... 1.0 m and interconnected 'butt-end' by means of welding or gluing.

To carry out welding or bonding, optical fiber length of about 1 mm from the end of the release of the containment, and then using a special tool - the cleaver produce shearing fibers. The purpose of this operation - to get a flat end perpendicular to the axis of 0V. Removing the shell 0V, release it from the module OC, cleaning of a hydrophobic gel and other necessary operations are performed using a set of tools placed in a special suitcase - case.

Fiber-to-end welding is carried out in a special welding machine. Modern welding machines for welding OB automatically perform the optimum mutual alignment RH choose the optimal welding parameters and monitor losses in spot welding. The welding process can be monitored visually in two coordinates on the liquid crystal display. These operations are carried out, for example, welding machine manufactured by FUJIKURA presented in Figure 3.1

Figure 3.1 - The welding machine manufactured by FUJIKURA

Place splicing spetsialnom fixed in the device, which is a heat-shrinkable tubing with a metal reinforcing rod, or in a special clip - metal V-shaped bracket.

United thus the optical fibers are placed in special trays, and they in turn in a special container, which is also fixed to those ends OC sections where it is not removed the protective outer shell. Such a container is called the optical coupling. There are various designs optical coupling. Figure 3.2 shows the optical coupling FUJIKURA production, in Figure 3.3 - the KRONE optical coupler.

Figure 3.2- The optical coupler connecting production FUJIKURA

Figure 3.3 - Optical coupling KRONE firms

Measurement of loss in optical fibers and cables are currently engaged in one of two ways.

The first - a two-point measurement method, which is divided into three types - the breaking of the method, and the method calibrated hitless dispersion.

Of these, the most widely used as a hitless nondestructive measurement method. When measuring the attenuation or OB OC RH input end of the test cut in the optical connector. This connector is connected with the reference emitter stabilized optical power and wavelength. To the output end OM, as the split in the OR, connect a calibrated optical power meter. Since the reference value of the power of the radiation source is known - Rae, is counting losses in OB negligible, we can assume that Pr = Pin. The measured output power value - Pout. Attenuation OF or OC is determined from the relationship:

, dB

Devices that produce such measurements are part of an optical tester. Optical testers are available in two versions:

- Option 1 - a reference transmitter and optical power meter is placed in a single package (eg, AQ215, company ANDO, Japan);

- Option 2 - a reference transmitter and optical power meter available in different housings, as two separate device (model K2702, K2503, K2505 and SIEMENS devices DIAMOND series, the company LONIIR, Russia and FOD, Russia).

Gauges of the power in these kits have two calibration - in power units of milliwatts and dBm (dBm - power level in dB relative to the magnitude Popt = 1 mW).

In practice it is more convenient to use the 2nd calibration. At the same time measure the power level of the transmitter output in dBm, then - the power level at the output of OB or OC. Subtracting the second reading of the first, to give the desired result.

The described method of measurement accuracy differs. Its main drawback - the need for access to both ends of the OC, it is often inconvenient for linear measurements.

Currently, the most widely used method of attenuation reflectometry measurements based on the measurement of that part of the Rayleigh scattering in the OB, which is circulated in the opposite direction (reverse). For this purpose, the fiber is introduced periodic sequence of optical pulses of duration and repetition period T. At the same time to the input end OM will return pulses at each time point. These pulses time lag from the input (reference pulse), reflected from the input end planes for a period of time equal to the double pulse to travel - in forward and backward directions. If the x-axis represents time (starting from t = 0 to the reference pulse), and the vertical axis - the average values ??of the amplitudes of these pulses for each value of the time, you get the so-called trace.

If the attenuation coefficient and backscatter coefficient at a given A for the fiber under test is constant along its length, the curve (trace) decreases from the beginning of OB exponentially. Scattering - statistical process. Therefore, the value of the pulse amplitude (ordinate) for the same time axis values ??(distances) will have some dispersion in each count (with periodic repetition of the probing pulses). Due to the statistical averaging of a large number of samples can be obtained pure line (exponential) dependence of the damping of the length of OB. However, an exponential curve to use awkward and difficult. So after averaging each sample is subjected to the logarithm operation, resulting in exponential (decaying) becomes the slope of the line. Thus counts on the ordinate calibrated in decibels. In the case where the reverse attenuation and Rayleigh scattering coefficients have sharp local change that indicates the presence of local inhomogeneities in OF, they appear on the trace in the form of steps or pulses. Figure 3.4 shows an example of the trace mode optical fiber length of 18.84 km.

Figure 3.4- Trace optical fibers 18,84 km

One of the advantages of the OTDR measurement method is that it is enough to have access to one end IA. Furthermore, using the OTDR can determine the distance to the local inhomogeneities, route length, length distribution inhomogeneities OF.

Modern OTDRs made a number of leading world companies:. ANDO (Japan), HEWLETT PACKARD, WAVETEK WANDEL & JGOLTERMANN, IIT, Minsk, Belarus, etc. Figure 3.5 shows a general view ANDO OTDR production.

Figure 3.5-OTDR company Anritsu (ANDO)

Measurement of chromatic dispersion. For modern trunk (zonal) PLAYBACK main factor limiting the length of the regeneration area is not fading, and introduced optic chromatic dispersion. The energy loss of an optical signal propagating in the CC compensated by use of intermediate optical amplifiers. In the process of propagation of optical pulses as a result they increase the duration of the chromatic dispersion. If the duration of the optical pulses becomes greater than the duration of a clock interval digital signals begin to cause errors in information transmission.

For transmission systems with speed STM-16 with a duration clock period = 400 ns expansion of optical pulses above this value begins with a length of more than 235 km section of a fiber G .652 and 800 nm - For G.655 OB by direct current modulation of the laser pump radiation. For STM-64 (10 Gbit / s) - respectively 36 km and 125 km of G.652 G.655 (for this rate = 100 ps). To increase the length of the regeneration area requires the use of compensation of chromatic dispersion, which entails the need to increase the gain of optical amplifiers, dispersion compensators as making large attenuation. Increasing the number of optical amplifiers besides increasing noise and also leads to an additional chromatic dispersion. From this it is evident the need for measuring the chromatic dispersion of optical pulses in the optical path FOTS.

Currently, according to Rec. ITU-T G.650, used three methods of chromatic dispersion measurement.

Currently, devices for measuring the chromatic dispersion produced by the following companies, and types of these devices are shown in Table 1 [PD].

Polarized mode dispersion (PMD) PMD measurement value .For there are several methods: 1) Fourier transform method; 2) wavelength scanning method; 3) a method of analysis parameters StOCes; 4) method of Poincarй sphere analysis; 5) a method of analysis using the Jones matrix. Such an amount of PMD measurement methods due to the fact that the need to measure arose relatively recently, due to the rapid increase in the speed and range of information transfer. This also explains the fact that, to date devices for PMD measurement is almost there.

The first company, which started production of equipment for the measurement of the PMD, is HEWLETT PACKARD - it has developed and launched a NR8509V device. The device with similar functions - AQ6330 released and the firm AN DO.

The operation of these devices is based on two methods - wave scanning and analysis of the Jones matrix. The measurement results are displayed on the display device in the form of curves PMD dependencies.

Compound of lengths of optical cable construction. Construction length of fiber optic cables for terrestrial FOTS. usually in the range of 3-6 km. (For submarines, especially for sea and ocean, - up to 25 km). The combination of these lengths is performed with the help of special devices, optical couplers (see. Figures 3.2 and 3.3). To this end, the ends of fiber optic cables that are designed for connecting (splicing) are exempt from the protective sheaths and reinforcing elements over a length of up to 0.5 m. Liberated optical fibers are thoroughly cleaned by washing with special fluids and tissues. In this case must necessarily be hydrophobic filler is removed from the optical fiber surface. To carry out these operations produced a set of special tools (see. Figure 3.8).

Figure 3.8 - Tool Kit for installation of optical cable

Below is a list of all necessary instruments, appliances and materials necessary for operations splicing of optical cables and fixing them all in the coupling.

Figure 3.9 shows the tools for cutting an optical cable: removal of the outer protective shell, remove shells modules, trimming Kevlar. With these tools, removed protective sheath fiber, then using a cleaver shown in Figure 3.10, is the fiber peeling for a flat end perpendicular to the axis of the fiber.

Figure 3.9- Tools for cutting an optical cable

Figure 3.10- Optical fiber cleaver Fujikura CT-02

Protective coating is removed from the fiber over a length of 15-20 mm. The following operation - on one of the fibers puts special tube -. Heat-shrinkable sleeve of the reinforcing element (typically a steel rod with a diameter of 1.0-1.5 mm diameter sleeve is 4.3 mm, length 30-50 mm (this operation can be performed RH before processing ends).

The treated fiber ends are fixed in special clamps welding machine (Figure 3.1) and is made of welding. In the process of welding is one of the specialists is at the other end of the length of the building OC, and monitors the quality of welding using a OTDR, communicating with the operator, producing welding special optical phone. This phone is connected to an optical fiber through its side surface at the bend. The criterion of the quality of welding is the magnitude of the losses introduced by the welding spot. They must conform to established standards (no more than 0.1 dB). After receiving the quality of welding is coming to this place heat-shrinkable sleeve, after which she, along with the fiber is placed in a special heating device, which is part of the welder, and anchoring is done shrinking sleeve. The resulting compound was placed in the grooves in the coupling for fastening.

4. Occupational Health and Safety

4.1 Analysis of dangerous situations

Businesses and communication structures, unlike the chemical, petrochemical etc. enterprises and facilities, at its negative impact on the biosphere, atmosphere and hydrosphere can be roughly attributed to the relatively 'clean.' However, current technical processes and equipment used in connection still are a source of negative effects on the environment and the human body.

When using the communications equipment in the PBX, LATS person is exposed to such adverse health effects as noise, vibration, ultrasound and infrasound, electrostatic dust. On the well-being is also influenced and the heat generated by the equipment. Since working PBX premises, LATS protected against the penetration of direct sunlight, the important role played by artificial lighting to ensure normal working conditions. All the above factors have an impact on labor productivity and the person's health.

Touching the metal current-carrying parts of the installation, which has no connection with the land and become live due to insulation failure, can lead to serious injury or death. To prevent electrical injuries that can be caused by contact with metal structures or electrical enclosures become live due to insulation damage, as well as to protect the equipment, arranged protective earth, which are intentional connection to the ground or with an equivalent metal parts of electrical installations, normally under voltage.

Fires on the PBX, LATS represent a particular danger, as are associated with large financial losses. The ATS premises LATS there are three main factors required for fire: combustible, oxidizer, ignition sources. Combustible components are: construction materials for aesthetic decoration, doors, floors, insulation of the connecting cables, racks, cabinets, fluid purification elements and computer components from dirt and other oxygen as an oxidizing agent of combustion processes, there is anywhere in the PBX space, LATS. . The source of ignition to the PBX, LATS may be electronic circuits of computers, devices used for the maintenance of power devices, air conditioners, where as a result of various disorders formed overheated components, electrical sparks that may cause ignition of combustible materials. In view of the above, will now be considered the following health and safety issues:

- Measures of fire prevention and evacuation plan for people in case of fire;

- Excess heat calculation indoor and selection of air conditioners for indoor installation and LATS;

- Calculation of artificial lighting.

To reduce occupational accidents Telecommunications held briefings. The following types of briefing:

- Induction training - is conducted for admission to work safety engineer on the program established by the director. It is made out of the control sheet, which is stored in the personal file of the employee;

- Primary instruction in the workplace - also carried out when applying for a job and is made in the check list. For related electrical equipment for 10-12 shifts conducted training in the workplace;

- A review - held every six months

- Unscheduled briefing - held in the event of a change of equipment, if there was an accident or an employee absent from the workplace for more than three months;

- Target instruction - is carried out in the performance of one-off jobs with high risk or particularly dangerous.

4.2 Creating the optimal working conditions of the operator

To confirm the correct operation of the transmission systems need to perform daily testing, monitoring, and debugging. All these operations are carried out on a computer. Therefore, to ensure safe and healthy working environment contributes to the ability to work, fewer errors, reduced fatigue at the end of the working day.

The activities of the operator caused a significant number of factors related to the characteristics of the work environment, workplace and functional duties of man.

The working environment in the system of human-machine (SCHM) - a direct impact on the operator's set of physical, chemical, biological and information factors, and workplace in SCHM - a space where to carry out labor activity, equipped with means of information display, controls and accessories . Workers are exposed to hazardous environment factors: electromagnetic fields, radio frequency, static, noise, poor lighting, and mental and emotional stress.

In this regard, in all production areas in the permanent workplace microclimate parameters must comply with CH 'microclimate of production rooms'. In the halls with a working computer technology in the workplace with desks, with camera work, etc. species microclimate parameters should be as follows.

During cold periods, the temperature of the air, its speed and relative humidity must be respectively: 14-22 degrees, 0.1 m / s, 40-60%; the temperature may range from 21 to 25 degrees, while maintaining the other parameters of the microclimate within the above limits.

Air conditioning should provide automatic control of microclimate parameters to the extent necessary for all seasons of the year, clean air from dust and pollutants, creating a slight overpressure in clean rooms to avoid the raw air intake. It should also be possible to individually adjust the air distribution to individual rooms. Temperature of the air supplied to the premises must not be below 19 degrees.

Placement of the workplace and the personal computer is necessary to make the following manner:

- A table with the keyboard and the display is at 750 mm from the floor;

- The display is placed on the table at a distance of 450-500 mm from the eye;

- A display screen located below eye level such that the angle between the normal to the center of the screen and horizontal eye level was about 20 degrees;

- The angle of inclination of the keyboard is 15 degrees;

- The necessary working documents are located at a distance of 450-500 mm from the left of the operator, the angle between the display and the document in the horizontal plane is 30-40 degrees (Figure 4.1).

Figure 4.1 Is the regular organization of the operator's station

Operating the seat should meet the following requirements:

-providing a body position where the load on the muscles and promotes optimal normal activities of the operator;

-creates possibility of changing working postures to relieve muscle tension and prevent general fatigue (which is especially important in an inactive state of the operator);

-provides free movement and body fixation relative to the work surface;

horizontally surface and backrest can be flat or contoured. Profiling is characterized by angles of inclination of the back (4-5 degrees towards the back) and the seat (10-15 degrees up from the seat) is also considered the best location, when the front edge of the seat retracted under the table 100-150 mm.

Thanks to recent advances in computer technology created displays that have a minimal impact on the operator due to radiation. Therefore, great attention should be paid to the proper selection of lighting, which is largely influenced by the considerable fatigue.

Lighting installations must provide uniform illumination using mostly reflected or scattered light distribution; they should not cause glare on the keyboard and other parts of the panel and on the screen in the operator's eye direction. To eliminate glare reflections on the screen from general lighting lamps, it is necessary to use special filters for screens, visors or have light sources parallel to glance at the screen on both sides. When placing sacking equipment is not allowed location of the display to each other. Local lighting is provided by lamps mounted directly on a countertop or table to its vertical panels, as well as built in in the remote hood. If there is a need for an individual light source, it should be able oriented in different directions and be fitted with a device to adjust the brightness and protective grille, protected from glare and reflection shine. Light sources with respect to the workplace should be positioned so as to prevent direct light from entering the eye. Protective corner fittings for these sources should not be less than 30. Ripple illumination used fluorescent lamps should not exceed 10%. When natural light should apply sun protection agents that reduce the differences between the brightness of natural light and the glow of the screen. As such means can be used with the metallized film coated controlled louvers or vertical lamellae. In addition, the recommended placement of windows on one side of the working space. In addition, each window should be light-diffusing curtains with a reflection coefficient of 0.5-0.7.

The recommended value of the differential brightness of the display surface, keyboard and documents is 1: 3, ie at the nominal value of the brightness of the screen 50-500 cd / sq.m. 300-500 lux illumination of the document. Reflections or shadows in the workplace while absent. The coefficient of reflection of light from surfaces immediately surrounding the workplace is 0.5. The ceiling is white (reflectance of 0.8), the floor darker than the walls (the reflection coefficient of 0.3).

4.3 Calculation of illumination LC

New equipment (multiplexers) for communication through fiber optic link between Stepnogorsk and Kokshetau installed in an existing LC. Upon delivery of the building were designed lighting, ventilation and other necessary parts. During prolonged operation times liable to variation. Therefore, questions about the illumination provided below, bears the character of verification of conformity to the norm.

There are general lighting system, a uniform or localized, and the combined lighting system, consisting of general and local lighting.

General lighting is uniform lighting for the premises, or part of the site open area when possible uniform luminance distribution over the entire illuminated area. In this case, generally lamps of a certain type and power are suspended at the same height and are distributed uniformly over the area.

Total localized lighting is used to illuminate the premises, or part of the site open area when consciously attained the uneven distribution of illumination on the area. In this case, type, capacity and height of suspension lamps can be different, and their distribution - uneven.

Local illumination serves only for illumination of the working surfaces. It may be stationary or portable.

The device in the room alone local lighting is prohibited. It must necessarily be supplemented by general lighting that creates a lighting auxiliary areas premises, softens shadows in the workplace and increases the brightness of secondary adaptation fields.

General lighting, arranged in a combined lighting system is usually performed as a uniform. It must be created in the location of jobs and in the last level of illumination zone at least 10% of the rate of the combined light, and not less than 30 lux at filament lamps and 100 lux - with fluorescent lamps. Creating illumination exceeding respectively 100 and 200 lux, not necessarily.

When combined light illumination rates are higher than in the general one. However, even with this combined lighting requires less power than the total, unless the working surfaces are limited in size and are located not too tight.

Uninterrupted operation of the lighting is always desirable, but in some cases it is very necessary, and then, in addition to the usual - 'working' - lighting, emergency lighting is arranged. Operating and emergency lighting referred kinds of lighting. Emergency lighting is different in two varieties:

- Emergency lights to continue serving for extinction under emergency lighting conditions of the working vision sufficient for temporary continuation of the staff;

- Emergency lighting for evacuation, which serves to provide for emergency lighting extinction working conditions of vision sufficient to secure release of people from the premises.

Emergency lighting for further work needs to be created on surfaces that require care in an emergency, illumination 5% of the values ??established for the corresponding normal operation. This light can be uniform, and localized, and local. Emergency lighting for evacuation should create along the lines of the main passages illumination of 0.5 lux. It is performed only as a general or localized uniform. For emergency lighting should, as a rule, use the same light source as the light of the desktop space.

Illumination levels for indoor communication centers take in accordance with the 'Instruction on the design of artificial lighting of communication enterprises', as well as regulations.

The light source is recommended to use fluorescent lamps. combined lighting system and adopted mainly for repair of premises, adjustments, cleaning and soldering apparatus and instruments, in other cases, should use a common system (localized or uniform) illumination.

Emergency lighting is required for all major operating communication centers Places (switches, cabinets, crosses). The degree of reliability of power and lighting loads communication nodes defined scheme of power supply enterprise (object) as a whole. On LC lighting powered by induction or AC shield their own needs, or directly from the network operating and emergency lighting of the building, where LC placed. If you have to Battery LC (having usually voltage 60V) lighting emergency lighting completely or partially, depending on the battery capacity, are powered by it, and emergency lighting, powered by a battery, is included with the disappearance of line voltage external sources alternating current.

The main communication rooms provide sockets for a voltage not more than 42V for the connection of portable lighting, soldering irons, drills, and 220 - for measuring instruments, vacuum cleaners, etc.

Modern electronic hardware and software managed and occupy a small area.

The LC installed PC for control, diagnostics and debugging equipment.

To illuminate the room with the mounted PC is used mainly fluorescent lamps, to be used primarily in areas with intense and accurate work and which have the following advantages:

- High luminous efficiency (up to 75 lm / W or more);

- Long service life (10 000 hours);

- Low brightness of the illuminated surface;

- More economical in power consumption;

- Lamp tube surface is heated a little (up to 40 - 50 degrees).

Calculation of lighting will perform the method of utilization of light. Dimensions of distinguishing objects are in the range 1-5 mm, the discharge of the visual work area defined 4th degree of accuracy, so it is economical system of general lighting, where lights are located in the upper zone, which provides uniform illumination of an area of ??34.72 m2 working space (length - 6.2 m, width - 5.6 meters) and a height of 3 m.

Of the reference data, select the most suitable lamp type LPP02 4'40. This lamp has the following technical data:

- The length of 1,294 m;

- Width of 0.245 m;

- The height of 0,115 m;

- Fully pylezaschischen;

- Type of lamp DTC 40-4.

For lamp DTC 40-4 luminous flux after 100 burning hours will be:

- Nominal 2100 lumens;

- Minimum 1890 lumens;

- The estimated value of 1995 lm.

Based on the calculation of the luminous flux, determine the luminous flux emitted by the lamp:

F_cv = 4 1995 = 7980, lm

The calculation method for the use of luminous flux ratio is calculated as follows:

F = (Е_n К_s S z) / (N ), lm (4.1)

Where Е_n - normability illumination, lx .; Ks - the safety factor that takes into account the aging of lamps, luminaires dust and dirt during operation, for building operators halls illuminated by fluorescent lamps and provided cleaning fixtures at least twice a year Ks = 1.5; S - illuminated by floor area in m2; z - illumination non-uniformity coefficient for fluorescent lamps with the location in the line z = 1,1; N - the number of rows of lamps; h - ratio of luminous flux.

The minimum illumination at a total rate of artificial light for this class of our premises is 300 lux, in accordance with SNIP II-4-79 «Natural and artificial lighting. Design standards ';

Since the height of the room does not exceed 3 meters, recommended ceiling mount fixtures. Then the height of the eaves hsv = 0 and the height of the working surface above the floor hp = 0. Thus, the formula of the suspension height:

h = H - h_св - h_р = 3-0-0 = 3, m

The distance between the rows of lamps is given by:

L = h, m (4.2)

Where L - the most advantageous ratio taken for light fixtures with fluorescent lamps K and the curve of 0.6; h - height of suspension.

L = 0,6 3 = 1,8, m

Knowing the distance between rows, we calculate the number of rows. Given that the fixtures will be placed along the long side of the room, the number of rows calculated by the formula:

N = B / L (4.3)

Where B - width of the room, which is equal to 5.6 m.

N = 5,6 / 1,8 3

We accept the number of rows of three.

To determine the utilization rate is necessary to find the index premises. space index i is determined by the formula:

i = (A B) / h (A + B) (4.4)

Where A - the room height 6.2 m; A - the width of the room 5.6 m; h - height of suspension 3 m.

i = (6,2 5,6) / 3 (6,2 + 5,6) = 34,72 / 35,4 1. (4.5)

According to this index space i = 1, we find the reflection coefficients:

Ceiling Rc = 70%, walls Pw = 50%, floor Rf = 10% [6] of Table 5-13 define the ratio of luminous flux of fluorescent lamps:

= 38%.

Substituting the resulting value calculation formula in the definition of the luminous flux 19, we get:

F = (300 1,5 34,72 1,1) / (3 0,38) = 17186,4 / 1,14 = 13972,7

The required number of fixtures in the series is given by:

n = F_рас / F_св (4.6)

n = 13972,7 / 7980 2, lamps

Now define the length of the row of luminaires.

With a length of one lamp type LPP 01 with lamps with a length of 40 MDC lsv = 1,310 m total length will be:

L_ov = n l_sv (4.7)

L_ov = 2 1,294 = 2,588, m

Possible loss of voltage in the lighting network is determined based on the need to have at the light source voltage is below a certain value.

To calculate the lighting network will take in this case the value of the permissible voltage losses in the grid equal to DU = 2%.

The calculation of the loss of voltage on the network based on a formula:

S = M / (C U) (4.8)

Where S - the conductor cross-section, mm2; M - load torque, kVt'm; C - constant depending on the voltage, current type and the conduction wire material. In Table 12-9 accept the coefficient C for copper wires with a two-wire AC or DC 220 V DC in equal 7.4.

Moment is determined by the formula:

М = n p [l₀ + (l/2 (n - 1))], kWm (4.9)

Where n - the number of fixtures in a row; l0 - the distance from the panel to the first lamp, m; l - the distance between the mounting fixtures, m; p - the power of one lamp, kW.

М = 2 0,16 [2,5 + (1,3/2 (2 - 1))]=0,32 3,15 = 1,008, kWm.

We accept wire size in accordance with the standard 2.5 mm2. Recalculated to determine the loss of the supply voltage. From Formula 4.10:

U = M / (C S) (4.10)

U = 1,008 / (7,4 2,5) = 1,008 / 18,5 0,06%

We have found that the voltage loss in the network is at a rate of 0.06% to 2%.

Thus, to perform the lighting network using copper wire grade SIP (2'0,75) for sockets using wires of the same brand.

4.4 Verification ground settlement

As measures to ensure electrical safety in LC and the operation of the equipment in the event of contact with live parts of metallic equipment become live due to the breakdown of the insulation of the grounding station equipment.

As a natural process using a metal grounding design, partially submerged in the ground, its calculated resistance spreading R = 49 ohms (water or other metal pipes). Grounding is supposed to perform the rod electrodes of the vertical length l m, a diameter of 5.6 mm or 40x40 mm steel angle, the upper ends of which are interconnected by a horizontal electrode length l m - steel strip section 4x12 mm, laid in the ground at a depth of 0.8 m. Specific earth resistance is 6 ohms:

р= 140, Ohm*m

The soil is clay, soil category 2.

Required spreading resistance grounding for the station should not exceed 2.4 ohms:

=125/I_g (4.10)

Where - current ground fault current is equal to:

=

Define the required grounding resistance artificial:

(4.11)

Where - the spreading resistance of the natural grounding, the Ohm.

, Ohm

Grounding switch type is selected in-line placed along the building where the station is located and LATS. Thus vertical electrodes arranged at a distance a = 5 m from each other.

Specify the parameters of the grounding switch by checking calculations. From the preliminary scheme it shows that we have adopted the total value of the grounding electrode of the horizontal and vertical number of electrodes n = 12. We calculate the estimated horizontal electrode resistance value (combined resistance) .

One vertical electrode according to the following formulas:

(4.12)

Where , d = 0,5 * b for band width b.

For a selected electrode t = Ѕ + t o

t = 5/2+0,8=3,3, m

Then we determined by the formula 4.3

Calculate R1 according to formula 4.5

Furthermore, bearing in mind that the grounding is adopted in a row that

n = 12 units, define the tables use the coefficients of earth (9).

We calculate the estimated resistance of the group grounding R th, according to the formula:

Rh =

Where Rv and Rh - spreading resistance of the vertical and horizontal electrodes, Ohm; n - number of vertical electrodes.

This resistance is less than a given r and Ri= 2.85 ohms; that provides security.

And so the projected grounding is located in one row consists of 12 vertical rod electrode length of 5 m and a diameter of 5-6 mm. And a horizontal electrode of the steel strip section length 60 m 4 * 12 mm, buried in the ground of 0.8 m. The ground conductor is attached to the apparatus reliable bolting and welding, to the earth electrode.

5. Environmental protection

5.1 General

When designing the building and reconstruction of cable lines must be carried out environmental safety requirements and protect public health, prescribe measures for nature conservation, sustainable use of natural resources, improvement of the environment.

To eliminate and redress the damage caused to the natural environment and the occurrence of adverse environmental impacts, particularly in the most vulnerable and dangerous areas (national parks and national parks, the migration places of animals, spawning fish of valuable species, coastal sea areas, rivers, permafrost, mountain terrain with scree and stone-fall events, etc.), in the construction of outside plant communication shall be provided environmental measures or means to compensate for the damage caused.

In the absence of local road communications cable line runs should, if possible, be placed on non-agricultural land or unsuitable for agriculture, as well as on forest land due to uncovered areas of forest plantations occupied little value, with the maximum use of existing firebreaks. For the construction of cable lines is permitted to provide a higher quality of land. In cases where the cabling is provided internally on arable land, the construction project should take into account the time limit production work for the period required for harvesting.

In the development of trenches and pits for installation on agricultural land (arable land, pastures, etc..) And forestry land by agreement with land users should be provided remediation activities temporarily allocated land for the construction period and the funds for the restoration of topsoil. In the projects construction of cable crossings over water barriers must be provided by measures which exclude the possibility of environmental pollution, as well as ensuring the preservation of fish stocks.

In the design of telecommunication and communication facilities should provide for economical land use and effective means of protecting the environment from pollution. Technical solutions should include the reduction of contamination to an acceptable level or eliminate harmful emissions into the atmosphere. The highest concentration of each harmful substance emissiruemogo now, should not exceed the maximum allowable concentration, to set standards [22].

In addition, in the construction business and communication facilities must be included issues related to recovery (reclamation) of land and bringing it to a condition suitable for further use.

Enterprises and communications facilities are a source of intense radiation fields of radio frequencies, so should be separated from the residential area of ??sanitary - protective zones whose size is determined by the degree of adverse effects on health and sanitary - hygienic living conditions.

Thus, to address the issues in the design and construction of communication facilities for environmental protection should include technological processes and production equipment, in which there should be no or not exceed the permissible values:

- Selection in the indoor air, the atmosphere and waste water;

- Harmful substances as well as the heat and humidity in the operating room;

- Noise, vibration, ultrasound;

- Electromagnetic fields, optical and ionizing radiation and static electricity.

should be allowed in the development of industrial and technological projects:

- Replacement and production of harmful substances harmless;

- Replacement of processes and process steps associated with the occurrence of noise, vibration and other hazards processes or operations for which there is no, or reduced the intensity of these factors;

- Replacement of the solid and liquid gaseous fuel.

Solution of environmental problems requires careful analysis, a systematic approach to solving the problem, that is, the study of all aspects of their environment, but also the influence of the environment on human society.

In addition to general issues of compliance Safety (rules for the operation of electrical, maintenance, loading and unloading, fire and so on. D.) The construction and operation of fiber-optic transmission systems need to comply with the specific safety requirements, which will be discussed in this chapter.

6. Feasibility study of the project

6.1 General

First of all, you need to clearly distinguish between the economic benefits and cost-effectiveness of new techniques and technologies.

The economic impact - is the end result of the application of technology noveshestva measured absolute values. They can be gains, reduce material and labor costs, the growth in production volumes and product quality, expressed in value and other indicators.

Economic efficiency - a measure defined by the ratio of economic benefit and cost gave rise to this effect, that is, or is associated with the size of the resulting profits, or gains in national income or gross domestic product (at the level of the country) with capital investments for the implementation of technical measures.

The effectiveness of the introduction of new technology should be to increase the number of products required for the company; improvement of its quality; increase in speed, the reliability of the transmitted information; the reliability of communication; improving the quality of customer service; increase in profits; increase profitability.

Calculations of economic efficiency of introduction of new technology designed to select the economic effect at low cost.

Economic efficiency of introduction of new technology is called the economic results of its applied.

The concept of new equipment includes new means of communication, means of mechanization and automation of production processes and networks, new and modernizirivannye mechanisms, instruments, structures, new and improved types of materials, new and more effective in comparison with the applicable both home and abroad, production processes and methods of production.

Therefore, baseline effectiveness of the implementation of new technology in the common system should be: performance increase of transmitted information; the efficiency of productive assets; indicators of quality products; quality of service indicators.

In all cases, these figures should be obligatory optimality criterion chooses new technology.

For one-time costs and ongoing include: capital costs; the cost of production; payback of capital costs.

6.2 Investments

Capital costs are determined by a one-time:

C = P + C_TR + C_INS + C_LS (6.1)

Where P - price of the equipment; C_TR - the cost of transporting the equipment to the place of use; C_INS - the cost of installation of the system hardware; C_LS - the cost of linear structures and transmission system.

This section is a table-name, the price and the total cost of equipment (Table 6.1).

Capital expenditures - economic effect of the introduction of new technology. To determine the total capital investment required for the implementation of new equipment and other new technology, you need to know the price of this equipment.

Indicators of capital costs for new equipment and in terms of the current production is compared by means of specific capital investments per unit of output is targeted.

Capital cost is calculated taking into account the general capital investments:

Where Ce - capital investment to purchase equipment; Cins - capital investment of installation of the system on site; Ctr - capital investment in the transport costs (5-10% of the cost of the equipment), Cc - capital investment for construction.

Table 6.1 - Investments

6.3 Operating costs

Annual operating costs are made up of the following cost items:

1. Wage state operating activities with deductions on social tax;

2. depreciation charges;

3. The cost of materials and spare parts;

4. Costs for electricity for industrial needs;

5. Other industrial and administrative expenses.

For the construction of fiber optic link on a site-KOCshetau Stepnogorsk require staff of 7 people (according to standards) (Table 6.2).

Table 6.2 - State Calculation

2. Social tax:

Z_st = (Z_osn*11%) /(100) (6.4)

Where Zosn - monthly state fee for a year, thousand tenge.

Z_st = 2904,0*11% /100=319,4, thous. tenge

3. Depreciation for the year (7% of the investment):

А = (С_tot*7%)/(100) (6.5)

Where С_tot - investment tenge.

Аline = 126082,0*7% /100 =8825,7, thous. Tenge

Ast=74620,5*10%/100=7462

A=8825,7+7462=16287,7

4. The property tax (1% of the residual value):

Н=(С_tot - А)*1% /100 (6.6)

Н=(126082-8825,7)*1% =1172,56, thous. tenge

5. Other expenses (4% of the above).

Make up 827.34 thous. tenge.

Table 6.3 - Operating costs

6.4 Operating income

Revenue calculations are made according to the formula:

Where - the range of services, - outgoing payments by type of exchange, - middle-income rate for the i-th type of communication services.

Calculation of income includes:

- Income from the connection of new subscribers;

- Income from subscription fees;

- Revenues from long-distance and international calls;

- Income from the rental channel, etc.

Then the total income is determined:

D _tot = 12*(D1 +………… Dn)+ Dед. (6.8)

Revenues anticipated in the 1st year of operation are given in Table 6.4. In this project, income is calculated according to the simplified form, ie. E. Will take into account only revenues from leased lines.

Table 6.4 - Revenue

6.5 Gain on sale of services

Profit from the sale of the enterprise communication services is defined as the difference between income from operations (or private enterprise) and operating costs, ie:

P = Dc - C

Gains (losses) are not related to the implementation of the main activities and call and bottom line may be a result of the sale of surplus property and other one-time services.

Other income may include: interest, dividends on securities owned by the company, the income from the lease of property and others.

The profit remaining after payments to the budget in the form of tax, will be the net income of the enterprise.

Profit is defined as:

P = Dod - Stot (6.9)

P = 21600,0- 4723,65 = 16876,35, thous. tenge

P = 16,876.35, thous.tenge including the VAT 2295.18 thous.tenge

Pcl = P - corporate tax (6.10)

The income tax is 20% (1st year), then:

Pcl = 14581,17 - 2916,23 = 11664,94, thous. tenge

6.6 Payback period

For the calculation of the economic efficiency of capital investments following expression may be used that through absolute payback:

Т = (C + C_awc) / (D_од - S) (6.11)

or

Т = C_ci / Eine Т< Т_n (6.12)

Where C, Cci - capital investment in fixed assets; Cawc - the amount of working capital (5% C); T - period of payback, years; Tn - standard payback period (Tn = 20 years).

As a rule, capital expenditure on the acquisition and implementation of new equipment, pay off the additional profit received from the sale of goods produced by this new technique, by increasing their prices while improving the quality of the goods, either by reducing production costs, the cost of these products, which provides a new more cost-effective equipment. Thus, the effect can be calculated as the difference in price:

Eine = (Pn - Po) Q (6.13)

Where Pn - a new unit price of higher quality; Po - old unit price; Q - volume of sales for the year; Eine - year of the introduction of new equipment, tenge.

Comparison of C_ci and Eine allows you to calculate the payback period of the new equipment and return on each ruble money spent now on new equipment.

The coefficient of efficiency of the new equipment cost (index, reverse payback period):

Е = Eine / C_ci = 1/Т (6.14)

The last indicator is often called the coefficient of return on capital investments in new equipment.

Payback is determined by:

Т_kp =C/ P_cl (6.15)

Т_kp = 11621,08/ 11664,94 = 0,99 =1, year

6.7 Profitability

In general, the effectiveness of any enterprise can be evaluated with the help of absolute and relative performance. Thus, an absolute measure is profit. However, this figure does not represent the full production efficiency. It reflects the utilization of resources, by which this profit obtained. Therefore, as the criterion of economic efficiency of production and the degree of profitability used by the relative size of profits, called the level of profitability.

Profitability is defined as the ratio of profit to the cost of fixed assets according to the formula:

Р = (D_од - S)/(C + C_awc)*100% (6.16)

Where on 01.03.09, the company C_awc up - 208,539.39 thous.tenge.

Р = 16876,35 /(11621,08+ 208539,39)=0,07

Profitability services (products) can be defined as the ratio of profit from the sale of (Preal) to operational expenditure E (cost of services).

Pe = Preal * 100/E (6.17)

Рe =11664,94 * 100/4723,65= 246,94

6.5 - Technical and economic indicators

Conclusion

Due to its high technical and economic indicators, digital fiber optic transmission systems are becoming more widespread.

In this thesis project the issues of construction of fiber optic portion of Stepnogorsk - KOCshetau The draft also proposed to build a network using the SDM-1 ECI Telecom's line equipment (Israel), which ensures reliability and high quality fiber optic performance.

The design calculations were made of the communication channels, and a portion of the length of the main parameters of regeneration of the optical fiber. It is the choice of fiber optic cable and the calculation of its most important characteristics.

Is a fiber optic pad description, technical characteristics of the proposed equipment SDH.

The project addressed issues of occupational health and safety as well as environmental issues.

Composed of a feasibility study of the project, which characterizes the economic feasibility of the project.

As a result, the project is expected to increase capacity and improve the quality of communication in this area. As a result, we should expect the growth in revenues from providing telecommunications services in the Akmola region.

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Application A

Additional information K-60

- Nominal attenuation at frequency amplifying section 252 kHz at a maximum temperature of soil dB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

- The difference between the attenuation constant slope circuit in a chain of environmental protection on the frequencies 247 kHz and 17 dB. . . . . . . . . . . . . 13

- The difference between the linear attenuation equalizer frequencies

247 KHz and 17 dB. . . . . . . . . . . . . . . . . . . . . . 17.0; 18.6; 20.2; 22; 23.6; 25

- Linear attenuation equalizer at the frequency of 252 kHz, dB. . . . . . . . . . .1

- Damping of two linear transformers, dB. . . . . . . . . . . . . . . . . . . . . . . . . . . 1

- Trunk equalizers:

1) the distance between them away. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60-8

2) attenuation at 252 kHz frequency, dB. . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

- Artificial line:

- The equivalent cable length, km. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3; 6

1) attenuation in dB at a frequency of 252 kHz IL3. . . . . . . . . . . . . . . . . . .7.4

IL6. . . . . . . . . . . . . . . . 14.9

IL3-IL6. . . . . . . . . . . . .22.3

2) attenuation in dB at a frequency of 12 kHz IL3. . . . . . . . . . . . . . . . . . . .2.2

IL6. . . . . . . . . . . . . . . . . 4.3

IL3-IL6. . . . . . . . . . . . . .6.5

- The range of variation gain ground AGC when the temperature changes

on 20С (from -2 to + 18С, from -10 to + 10С, from +10 to + 30 ° C), dB; for balanced trunk cable at frequencies of 12 kHz. . . . . . . . . . . . . . . . . . . . . . .1

252 kHz. . . . . . . . . . . . . . . . . . . . 2.1

- AGC adjust limits on control frequency, dB:

1) for the two-frequency amplifiers with AGC:

flat (248 kHz). . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 4

oblique (12 kHz). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 3.5

2) for the three-frequency amplifiers with AGC:

flat (248 kHz). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .± 4

inclined (12kHz). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 3.5

curved (80kGts). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .± 3.5

- Error frequency AGC dB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ± 0.5

- Accuracy of the temperature AGC dB. . . . . . . . . . . . . . . . . . . . . . . . . .± 0.2

- The maximum gain of the amplifier stations on frequency 252 kHz

at the maximum AGC regulators, dB:

1) for the UAI. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

2) to the SAI, OP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

- Minimum gain amplifier stations on the frequency of 252 kHz, dB:

1) for the UAI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

2) to the SAI, OP. . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49

- Psophometric average noise power, pW, at zero

relative level introduced into the channels of the PM system:

linear path at the transmission distance of 2500 km. . . . . . . . . . . . . . . . 7500

equipment two terminal stations with the bass end of the channel

Bass and transit facilities. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .500

HF transit equipment (for primary groups). . . . . . . . . . . . . . . . . . . . . . . . .200

- Allocating channels equipment (4, 12, and 24 channels) in a path:

direct passage. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . .30

isolating and introducing four channels. . . . . . . . . . . . . . . . . . . . . . . . . . 350

- Power noise level in the spectrum of the channel PM

(248-252 kHz), powered by input line amplifier in dB:

UAI and SAI -2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -132

SAI -3 and OP. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -129

Figure 1 - Scheme of frequency transformation of K-60P transmission system

Figure 2 - The road Stepnogorsk - KOCshetau

Application B

Figure 1 - Block diagram of a synchronous multiplexer SDM-1

Application C

Proposals for selection Timing sources SDH network.

There is a list of recommendations ITU sets standards for most timings: G.803, G.810, G.811, G.812, G.823, G.824.

The main components of the circuit SDH synchronization are:

- a primary reference clock generator - PRC determines the long-term stability of the frequency synchronization;

- secondary (slave) oscillator - SSU (Synchronization Supply Unit), a clock signal regenerating circuit after passing the network elements and serves as a temporary substitute for part of the network in case of failure or loss of connection PRC therewith;

- internal clock in SDH network elements - SETS (SDH Equipment Timing Source), provides greater flexibility in the choice of signals for synchronization.

These clock sources have the following characteristics.

There are two types of PRC - Autonomous and RC on the GPS satellite navigation system (ITU G.811):

- output interface 2048 MHz and 2048 kbit / s (ITU Recommendation G.703);

- own accuracy: ± 110E-11.

The secondary (slave) clock generator SSU - the second level of the quality of the synchronization equipment hierarchy. Its characteristics (ITU Recommendation G.812):

- input interface 2048 MHz, 2048 kbit / s (ITU Recommendation G.703);

- output interface 2048 MHz and 2048 kbit / s (ITU Recommendation G.703);

- own accuracy: 210E-9 ... 310E-7.

SDH synchronization source in SETS equipment connected to the input or output signals through interfaces of the network element, or transmitting payload synchronization interfaces.

Features (ITU Recommendation G.813):

- clock inputs:

- T1 source - SDH, (STM-N) (G.707);

- T2 power - PDH, 2048 kbit / s (G.703 / 704);

- T3, the source - clock 2048 MHz or 2048 kbit / s (G.703 / 704);

- clock outputs:

a) T4, external synchronization signal 2048 MHz (G.703);

b) T4, 2048 kbit / s (G.703 / 704).

- own accuracy: ± 4,6 • minimal 10E-6.

SETS Block diagram shown in Figure 1.

Figure 1 - Synchronization SDH equipment

For transporting the synchronization signal in the SDH network typically used payload signals (traffic). To meet the quality standards of international digital connections (G.822) the primary clock source must comply with PRC standard (G.822).

For secure synchronization, SDH multiplexers network should have multiple redundant clock sources:

- PRC or the source of the signal quality is not lower than PRC;

- Secondary clock (SSU);

- Your own timing source (SETS).

The maximum allowable number of network elements of the network (NE) between the two SSU is 20, the maximum number of SSU in the chain synchronization - 10. Total number of consecutive sync items (NE and SSU) shall not exceed 60.

Self-healing SDH network structure in a crash on the network perform automatic reconfiguration of the synchronization, which is controlled by a time-marker and priority switching of SDH equipment. The criterion for switching sources in synchronization network elements are the following events:

- LOS (loss of signal);

- LOF (loss cycle);

- AIS (Alarm Indication Signal);

- TMA (alarm synchronization marker);

- Exc.BER (10 bit error rate).

Information about the quality of the timing source is transmitted in bits 5-8 S1 byte header MSOH STM-1 frame. Table 2 contains the information contained in the byte synchronization marker SSM.

Table 2 - The information in byte synchronization marker SSM

Note: Notes to Table 2:

The PRC, SSM when receiving the value of bits 5-8, 0010, each network element is synchronized with this reference oscillator Q1 quality.

SSU-A, when receiving SSM bits 5-8 the value 0100 indicates the use of a timing source, respectively G.812T ITU-T with a level of quality Q2.

SSU-B, Q3 quality is almost an order of magnitude lower than for transit SSU.

SEC, SSM source clock multiplexer synchronization marker byte is sent when the priority list are no other sources of clock signals.

Quality is not known: the SSM byte is transmitted by the network element in the STM output as long as the internal crystal oscillator is not synchronized with the incoming clock signal sources.

To synchronize the unused byte synchronization marker with a value of 5-8 bits 1111 (Q6) is transferred automatically in the case of SDH-sync port in the opposite direction. This prevents the formation of the loop synchronization.

The basic requirement when planning the synchronization network is the availability of primary and backup synchronization signal pathways, in compliance with the required hierarchy, as well as the lack of opportunities for a closed loop synchronization.

Signal distribution network with land-KOCshetau Stepnogorsk shown in Figure 1

Figure 1 - Distribution of SDH network synchronization with the site-KOCshetau - Stepnogorsk.

The network element located in the city of KOCshetau appointed master (master node). On it sync signal from an external reference source PRC (Q1) at a frequency of 2048 kHz from the INSM. He is the first priority of the planned network. A highly accurate time generator is a strategic object, and therefore his whereabouts secret.

An alternative source for the synchronization master node SDH network is designed AMTS in KOCshetau. Summary Q1 synchronization is distributed in the STM-1 signal successively to the nodes Shchuchinsk, Stepnogorsk Saul and with first priority for these sites (Table 3).

Table 3 - Distribution synchronization sources

Functional timing circuit designed SDH network is shown in Figure 3.