Equipment for HF communication. RF communication systems for LPP

Page 16 of 21

The design of the power line, determined by its main purpose - the transmission of electrical energy to the distance, allows it to be used to transmit information. High level of operation and large mechanical strength lines ensure the reliability of communication channels close to the reliability of channels by cable lines Communication. At the same time, when carrying out communication channels for information transfer, it is necessary to take into account the features of lines that make them use for communication purposes. Such a feature is, for example, the presence at the ends of the lines of substation equipment, which can be represented as a chain of consistently connected reactive and active resistance to the wide limits. With these resistances through the tires of substations, the connection is formed between the VL, which leads to an increase in the communication path. Therefore, to reduce the influence between channels and attenuation with the help of special barriers, the pathways of high frequency towers in the direction of substations are blocked.
Significantly increase the attenuation of the branch from VL. These and other features of lines require a number of activities to create information transfer conditions.
The device of the RF channels on the distribution networks 6-10 kV is associated with significant-equipment due to the specifics of the construction of these stresses. At the plots of trunk lines 6-10 K in between adjacent switching points there are big number Sweeping, lines are partitioned by disconnectors and switches, network switching schemes are often changed, including automatically, due to the greater damage to these stresses, their reliability is lower than B71 35 kV and higher. The transmission of signals in distribution networks depends on many factors affecting the attenuation of the signal: from the length and number of exhaust, the material of the wire lines, load, etc. The load may vary widely. At the same time, the disconnection of individual exhales, as studies show, sometimes not only does not reduce the attenuation, but, on the contrary, due to the violation of mutual payment compensation between neighboring exhausts increases it. Therefore, the channels even a small length have a significant attenuation and work unstable. At work of the channels, damage to the insulators, poor-quality wire connection and the unsatisfactory status of the switching equipment contacts, these defects are sources of interference, commensurate with the level of the transmitted signal, which can cause termination of the channel and damage to the instrument. The presence on the lines of the partitioning devices leads to a complete cessation of the operation of the RF channel if they are turned off and grounding one of the line sections. The noted disadvantages are significantly limited, although they do not exclude, the use of 6-10 kV lines for the organization of RF channels. Nevertheless, it should be noted that the wide distribution of RF communications on distribution networks has not yet received.
For the purpose of the RF, the communication channels over power lines are divided into four groups: dispatching channels, technological, special and linear operational communication channels.
Without stopping in detail on the use and purpose of each channel of channels, we note that for dispatching and technological channels telephone communication used mainly strip of tonal frequencies 300-3400 Hz<300-2300). Верхняя часть тонального спектра (2400-3400 Гц) не пользуется для передачи сигналов телеинформации. Современная комбинированная аппаратура позволяет организовать в этом спектре до четырех независимых узкополосных каналов телеииформации.
The channels of linear operational communications are used to organize the dispatcher communication with the extensive power line operating on the highway or substations by repair teams, when there is no permanent connection with them. For these channels, simplified transportable and portable telephone equipment is used.
According to the degree of complexity of HF, the channels are divided into simple and complex. Channels consisting only of two sets of terminal RF equipment are called simple. Complex channels are in their composition intermediate amplifiers or several sets of terminal equipment (at the same frequencies).

Equipment of high-frequency communication channels on VL.

Connecting communication equipment to the wires of the power line is carried out using special devices of the so-called equipment of the attachment and processing line consisting of a communication condenser, a barrier and protection elements.

Fig. 21. Scheme of high-frequency communication channel on VL
In fig. 21 shows a scheme for the formation of a communication channel on Vl. Signal transmission of high frequency currents is carried out by transmitters of sealing equipment J, placed at both ends of the VL at substations A and V.
Here, as part of the sealing instruments 1, there are receivers that make the modulated currents of the HF and their conversion. To ensure the transmission of signal energy of the RF voltage by wires, it is sufficient to process at each end of the line one wire using a barrier 5, a communication condenser 4 and an attachment filter 3, which is connected to the sealing equipment 1 using the RF cable 2. To ensure the safety of staff work on the attachment filter When the RF channel runs the grounding knife 6.
Attaching high-frequency equipment according to the scheme Fig. 21 Wears the name phase-land. Such a scheme can be used to form single-channel and multi-channel information transmission systems. Other connection schemes also apply.
If you need to connect to the power transmission line installed on the line track (telephone mobile hardware repair team, the equipment remotely controlled VHF of the radio station, etc.), are usually used, as a rule, antenna connection devices. As an antenna, segments of an isolated wire of a certain length or section of the threshing cable are used.
High-frequency (linear) Barrel has a high resistance for the operating frequency of the channel and serves to boom the path to these currents, reducing their leakage towards the substation. In the absence of a barrier, the attenuation of the channel may increase, since the slight input resistance of the substation shunt the RF channel. The barrier consists of a power coil (reactor), configuration element and protection device. The power coil is the main element of the bar. It must withstand the maximum working currents of the line and currents of the KZ. The power coil is made of copper or aluminum wires of the appropriate section wound on wood-layered plastic rails (delta wood) or fiberglass. The ends of the rivers are fixed on metal crosses. On the upper cross, the configuration element with protective arresters is attached. The setup element serves to obtain relatively high resistance of the barrier on one or several frequencies or frequency bands.
The configuration element consists of capacitors, inductors and resistor coils and turns on in parallel
Power coil. The strength coil and the element of the tuning of the barrier are exposed to atmospheric and switching overvoltages and KZ. The role of protection against overvoltages, as a rule, performs a valve arrester consisting of a spark gap and a nonlinear vilto-resistor.
In the electrical networks of 6-220 kV, the Barreliers of the PT-600-0.25 and KZ-500, as well as barriers with the steel core of the TBS-100 types-100 and V / 100B, differing from each other with a rated current and inductance, stability and geometric parameters The power coil, as well as the type of configuration item and its protection.
Barrels are crashed into a phase power line conductor between a linear disconnector and a communication capacitor. High-frequency barriers can be mounted in a suspended form, on support structures, including on communication condensers.
Communication capacitors are used to connect RF equipment to the air line, while the currents of industrial frequency leakage are discharged through the communication condenser to the ground, bypassing the high frequency instrument. Communication capacitors are calculated on phase voltage (on a network with grounded neutral) and on linear voltage (on a network with an isolated neutral). In our country, condensers of communication of two types are produced: CMR (communication, oil-filled, with an expander) and SMM (communication, oil-filled, in a metal case). For different stresses, condensers are equipped with separate elements connected in series. Communication capacitors can be installed on reinforced concrete or metal supports with a height of about 3 m. For the isolation of the lower element of the capacitor of the CMP body from the body of the support, special porcelain coasters are used.

The attachment filter serves as a link between the condenser of the communication and HF equipment, separating the high voltage line and the installation of the weak current, which is the sealing equipment. The attachment filter ensures that the security of the personnel and the protection of the hardware of high voltage, since the path for the flow of industrial frequency leakage currents are formed by grounding the low-end condenser. With the help of the attachment filter, the wave resistances of the line and high-frequency cable, as well as compensating for the reactive resistance of the communication condenser in the specified frequency band, is carried out. Attachment filters are performed according to transformer and autotransformer schemes and together with communication capacitors form strip filters.
The largest distribution in the organization of RF channels of communication on the power lines of the enterprise was obtained by an OFP-4 attachment filter (see Fig. 19). The filter is enclosed in a steel welded body with a passing insulator to attach a communication condenser and cable funnel to enter the Cable RF. On the wall of the case, a discharger is attached, having an elongated heel to connect the grounding and intended to protect elements of the filter of overvoltages. The filter is designed to attach the RF equipment according to the phase-land scheme complete with communication condensers with a capacity of 1100 and 2200 PF. The filter is set, as a rule, on the support of the communication condenser and is attached to the support bolts at an altitude of 1.6-1.8 m from the ground level.
As noted, all switching in the connections filter circuits are made when the grounding knob is enabled, which serves to ground the lower cover of the communication capacitor during the work of the personnel. A single-pole disconnector for a voltage of 6-10 kV is used as a grounding knife. Operations with a grounding knife are made using an insulating rod. Some types of addition filters have a grounding knife mounted inside the housing. To ensure safety in this case, a separate grounding knife must be installed.
The high-frequency cable is used for electrical connection of the attachment filter (see Fig. 21) with transceiver equipment. When connecting the hardware to the diagram according to the phase diagram - the land applies coaxial cables. The most common is the high-frequency coaxial cable of the RK-75 brand, an internal conductor (single-core or stranded) which is separated from an external braid with insulation from a high-frequency dielectric. The outer screen braid serves as a reverse wire. The external conductor is concluded in a protective insulating shell.
The high-frequency characteristics of the RK-75 cable, as well as conventional communication cables, are determined by the same parameters: wave resistance, kilometer attenuation and speed of electromagnetic waves.
The reliable operation of the RF channels according to the WL provides high-quality and regular execution of planned-preventive work, providing for a whole range of works on the equipment of RF communications on VL. To perform prophylactic measurements, the channels are output from work. The prophylactic service includes planned tests of equipment and channels, the frequency of which is determined by the state of the equipment, the quality of operational service, taking into account preventive work and is set at least 1 time in 3 years. Unplanned channel checks are performed when changing the RF path, damage to the equipment and in the unreliable operation of the channel due to the violation of the regulated parameters.

The MC04-PLC Digital Communication System is designed to organize telemechanic channels (TM), data transmission (PD) and telephone channels (TF) on high-voltage power lines (LEP) 35/10 kV distribution network. The equipment ensures the transfer of data on high-frequency (HF) communication channel in a 4/8/12 kHz band in the frequency range of 16-1000 kHz. The connection to the LAM is made according to the phase scheme - the land through the communication capacitor and the attachment filter. Connecting the HF End of Equipment to the attachment filter is asymmetric and is performed by one coaxial cable.

The equipment is made with a separated and adjacent location of the bandwidth of the reception and transmission directions.

Functionality:

The number of HF channels of 4 kHz width - up to 3;
Channel mode: analog (frequency separation) and digital (temporary separation);
Modulation of low-frequency digital stream - QAM with a division by 88 subcarriers OFDM;
Modulation of the RF spectrum is amplitude with the transmission of one sideband of the frequency frequency of AM OB;
adaptation of the bit rate of the digital stream (CPU) to the changing signal / noise ratio;
Telephony Interfaces: 4-wired 4W, 2-wire FXS / FXO;
The number of telephony channels in each RF channel - up to 3;
Converting ADASE alarm to the FXS / FXO subscriber alarm;
dispatch and subscriber connection according to the AdAse protocol on one TF channel;
Digital TM and Data Transmission Interfaces: RS232, RS485, Ethernet;
Management and Monitoring Interface - Ethernet;
Built-in analyzer of transmission / reception / reception of the RF path, error meter, temperature.
Registration of faults and signaling in non-volatile memory;
digital correction - transit channels on intermediate substations without loss of quality;
Monitoring - MC04-Monitor: Configuration, Setup, Diagnostics;
remote monitoring and configuration through the built-in RF service channel;
SNMP support - when equipped with a S-port network module;
radial and tree-like monitoring schemes of remote semi-plates;
Power supply: network ~ 220 V / 50 Hz or constant voltage 48/60 V.

Main settings
Operating frequency range 16 - 1000 kHz
Width of the working strip 4/8/12 kHz
Nominal peak power of the envelope of the RF signal 20/40 W
Maximum transmission rate of the CPU in the 4 kHz strip (adaptive) 23.3 kbps
The depth of the ARU adjustment with the error factor is not more than 10-6 at least 40 dB.
Permissible damping line (with no interference) 50 dB

Power consumption 220 V or 48 V - no more than 100 W.
Overall dimensions of block - 485 * 135 * 215mm.
Weight no more than 5 kg.

Operating conditions:

- ambient temperature from +1 to + 45 ° C;
- relative air humidity up to 80% at a temperature plus 25 ° C;
- atmospheric pressure not lower than 60 kPa (450 mm Hg. Art.).

Design and composition of equipment:

The Digital Three-channel MC04-PLC Communication System includes two 19 inches 3U blocks in which the following functional structural nodes (fees) are installed:
IP01- power supply, network entry 220V / 50Hz, output + 48V, -48V, + 12V;
IP02- power supply, input 36 ... 72V, output + 48V, -48V, + 12V;
MP02- multiplexer of TM channels, PD, TF, G.729 codec, a digital echocompensator;
MD02- modulation / demodulation of the CPU in analog RF signal, monitoring and management;
FPRM - linear transformer, attenuator and 4-contour filter PRM, PRM amplifier;
FRD - 1/2-contour PDP filter, high-resistant impedance outside the PD band;
Um02 power power amplifier, digital indication of PDA levels, indication of accidents.
TR01 is the transit of the contents of the RF channel between the blocks, is installed on the Place of MP02 boards.

Information for order

The number of MP02 boards corresponds to the amount of basic RF channels with a band of 4 kHz, configured on the MD02 board - from 1 to 3. In the case of a transit of one of the RF channels between the blocks on the intermediate substation to the MP02 board, the TR01 transit board is installed, providing the reception / transfer of the contents of HF Channel without conversion to analog form.
The unit has two main versions of the peak power of the envelope of the RF signal:
1p - one amplifier Um02 and one FRD filter, power of the RF signal - 20 W;
2p - there are two amplifiers Um02 and two FIS filters, the power of the RF signal is 40 W.

The designation of the block includes:
- the number of VF channels involved 1/2/3;
- execution by peak power of the envelope of the RF signal: 1p - 20 W or 2p - 40 W;
- Types of custom joints of each of the 3-RF channels / boards MP-02 or TP01 board;
- Block supply voltage - network ~ 220 V or constant voltage 48 V.
On the MP-02 board, the default is RS232 and Ethernet digital interfaces that are not specified in the block designation. .

Communication channel is a set of devices and physical environments transmitting signals. With the help of channels, the signals are transmitted from one place to another, and also tolerated in time (when storing information).

The most common devices that are part of the channel: amplifiers, antenna systems, switches and filters. A pair of wires, a coaxial cable, a waveguide, a medium in which electromagnetic waves are often used as a physical environment.

From the point of view of communication technology, the most important characteristics of communication channels are distortions that are subjected to signals transmitted on it. There are distortions linear and nonlinear. Linear distortion consist of frequency and phase distortion and are described by the transitional characteristic or, which is equivalent to an integrated channel transmission coefficient. Nonlinear distortions are given nonlinear dependencies indicating how the signal changes when passing over the communication channel.

The communication channel is characterized by a set of signals that are sent on the transmitter end, and the signals that are accepted at the receiving end. In the case when the input and channel output signals are functions defined on a discrete set of argument values, the channel is called discrete. Such communication channels are used, for example, in pulsed modes of operation of transmitters, in telegraph, telemetry, radar.

Several different channels can use the same technical line of communication. In these cases (for example, in multichannel communication lines with frequency or temporal separation of signals), the channels are combined and separated using special switches or filters. Sometimes, on the contrary, one channel uses several technical communication lines.

High Frequency Communication (HF Communication)- This is a type of communication in electrical networks, which involves the use of high-voltage power lines as communication channels. On the wires of the power lines of the power grid flows a current current of 50 Hz. The essence of the organization of the RF communications is that the same wires are used as a signal transmission over the line, but at another frequency.

The frequency range of the RF communication channels is from tens to hundreds of kHz. High-frequency bond is organized between two adjacent substations, which are connected by the power line with a voltage of 35kV and above. In order to enter the tires of the substation distribution device, and the communication signals to the appropriate communication kits are used by high-frequency barriers and communication capacitors.

The RF Capacity has a small resistance to the current industrial frequency and a large resistance at the frequency of high-frequency channels. Communication condenser - On the contrary: has a large resistance at a frequency of 50 Hz, and at the frequency of the communication channel - small resistance. Thus, it is possible to enter the substation tires exclusively with a frequency of 50 Hz, per set of RF communications - only signals at high frequency.

For receiving and processing RF signals on both substations, between which the RF communications is organized, install special filters, signatures of signals and equipment kits that implement certain functions. Below will consider which functions can be implemented using HF-links.

The most important feature is the use of the RF channel in the relay protection devices and automation of the substation equipment.The RF communication channel is used in defenses of lines 110 and 220kV - differential-phase protection and directional high-frequency protection. At both ends, the LAP sets the protection kits that have a connection between themselves on the RF communication channel. Thanks to the reliability, speed and selectivity, protection using the RF communication channel is used as the main for each VL 110-220KV.

Channel for transmission of relay protection signals of power lines (LEP) is called channel relay protection. In the technique of RZa received the greatest distribution of three types of HF Protection:

filter directional,

remote with RF blocking,

differential phase.

In the first two types of protection on a RF channel with an external short circuit, a solid signal of the RF blocking is transmitted, in differential phase protection via the relay protection channel, voltage pulses are transmitted. The duration of pulses and the pause is approximately the same and equal to half the industrial frequency period. With an external short circuit, transmitters located at both ends of the line work in different semi-of industrial frequency. Each of the receivers receives the signals of both transmitters. As a result, with an external short closure, both receiver take a solid blocking signal.

With a short closure on the protected line, the phases of the manipulating voltages are shifted and the time intervals appear when both transmitters are stopped. In this case, an intermittent current occurs in the receiver used to create a signal acting on shutding the switch of this end of the protected line.

Typically, transmitters at both ends of the line operate at one frequency. However, on the lines of high length, there are sometimes relay protection channels with transmitters operating on different RF or PA frequencies with a small interval (1500-1700 Hz). Work on two frequencies makes it possible to get rid of the harmful effects of signals reflected from the opposite end of the line. Relay protection channels use a special (dedicated) RF channel.

There are also devices that, using the RF communication channel, determine the place of damage to the power lines. In addition, the RF communication channel can be used to transmit signals, SCADA, SAU and other ECU control systems. Thus, on the high-frequency channel channel, you can control the mode of operation of substations equipment, as well as transmit control commands of switches and various functions.

Another function - telephone communication function. The RF channel can be used for operational negotiations between adjacent substations. In modern conditions, this feature is not relevant, as there are more convenient ways of communication between service personnel of objects, but the RF channel can serve as a backup channel of communication in case of an emergency when there is no mobile or wired telephone.

Communication channel over power lines - a channel used to transmit signals in the range from 300 to 500 kHz. Different communication circuits are used. Along with the phase scheme - the Earth (Fig. 1), which occurred most often due to its economy, schemes are applied: phase - phase, phase - two phases, two phases - land, three phases - land, phase - phase of different lines. HF Barrier, communication capacitor and connection filter used in these schemes are the equipment processing equipment for the organization by their wires of RF communication channels.

Fig. 1. Structural diagram of a simple communication channel over the power line between two adjacent substations: 1 - HF barrel; 2 - communication condenser; 3 - attachment filter; 4 - RF cable; 5 - device of the TC; in - telechange sensors; 7-receivers of teleximents; 8 - devices relay sewn or (s) teleavtomatics; 9 - PBX; 10 - PBX subscriber; 11 - Direct subscribers.

Treatment of lines is needed to obtain a stable communication channel. The attenuation of the RF channel via the treated power transmission is almost independent of the lines switching scheme. In the absence of processing, the relationship will be interrupted when it is disconnected or grounded by the ends of the LAM. One of the most important communication problems on power lines is the lack of frequencies due to low transient attenuation between lines having a connection through the substation bus.

RF channels can be used to communicate with operational-exit brigades that carry out the repair of areas of damaged power lines eliminate damage in electrical installations. For this purpose, special portable transceivers use.

The following RF apparatus is used, connected to the treated LPP:

combined equipment for telemechanic channels, automation, relay protection and telephone communication;

specialized equipment for any one of the listed functions;

further communication equipment connected to the LAM through the attachment device directly or using additional blocks to shift the frequency and increase the transfer level;

pulse control equipment for lines.

The high-frequency communication equipment with digital processing of signals (AVC) was developed by Radis Ltd., Zelenograd (Moscow) in accordance with the technical specifications approved by CDU UES of Russia *. The WCC was adopted and recommended for the production of the Interdepartmental Commission of FGC UES OJSC in July 2003, has a certificate of state standard of Russia. The equipment is made by the company "Radis LTD" since 2004
* Currently, OAO Co-CDU UES.

Appointment and opportunity

AVC is intended for organization 1, 2, 3 or 4 channels of telephone communication, telemechanical information and data transmission on LPP 35-500 kV between the dispatching area of \u200b\u200bthe district or enterprise of electrical networks and substations or by any objects necessary for dispatching and technological management in power systems .

In each channel, a telephone connection can be organized with the possibility of transmitting in the submal spectrum of telemechanical information by embedded or external modem or data transmission using the built-in or external user modem.

Modifications of aw

Combined option

terminal AVTS-C

Execution

In WCC, methods and means of digital signal processing are widely used, which makes it possible to ensure accuracy, stability, manufacturability and high reliability of equipment. The AVC modulator / demodulator of the AM OBR, transmultiplexer, adaptive equalizers, built-in telemechanics modems and service modems of control signals are made using signal processors, plis and microcontrollers, and telephone automatic controls and control unit are implemented on the basis of microcontrollers. As an embedded modem for transmitting data in the channel, the STF / CF519C modem of the company "Analyst" is used.

Specifications

Number of channels	4, 3, 2 or 1
Range of operating frequency	36-1000 kHz
Nominal frequency band of one transmission direction (reception):
- for single-channel	4 kHz
- For two-channel	8 kHz
- For three-channel	12 kHz
	16 kHz
Minimum frequency variation between the edges of the nominal transmission and reception bands:
- for single and two-channel	8 kHz (ranging to 500 kHz)
- For three-channel	12 kHz (ranging to 500 kHz)
- for four-channel equipment	16 kHz (ranging to 500 kHz)
- single, two-, three and four-channel equipment	16 kHz (in the range from 500 to 1000 kHz)
Maximum peak transmitter power	40 W.
Sensitivity receiver	-25 dBm.
Selectivity of the receiving tract	meets the requirements of IEC 495
Range of adjustment of the ARU in the receiver	40 dB.
The number of built-in telemechanics modems (speed 200, 600 bodes) in each channel
- for the speed of 200 baud	2
- for speed 600 baud	1
The number of connected external telemechanics modems in each channel	No more than 2
Number of built-in data modem (speed up to 24.4 kbps)	Up to 4
The number of connected external modems for data transmission	Up to 4
Nominal resistance for HF
- unbalanced	75 Ohm.
- balanced	150 Oh.
Operating temperature range	0 ... + 45 ° С
Food	220V, 50 Hz

Note: At a balanced output, the average point can be connected to the ground directly or through a resistor 75 Ohm with a power of 10W.

Short description

The AVTS-NC terminal is set at the dispatching point, and AVTS-RF is on the support or nodal substation. Communication between them is carried out on two phone pairs. Frequency bands occupied by each communication channel:

Overlapping attenuation between the AVTS-NC and AVC-RF terminals is not more than 20 dB at the maximum channel frequency (characteristic resistance of the 150 Ohm line resistance).

Efficient bandwidth of each channel in AVC 0.3-3.4 kHz, and it can be used:

Telemechanics signals are transmitted using embedded modems (two to Speed \u200b\u200b200 Bud, the average frequency is 2.72 and 3.22 kHz or one to the rate of 600 bodes, the average frequency of 3 kHz) or external user modems.
Data transmission is carried out using the built-in modem STF / CF519C (depending on the parameters of the line speed can reach 24.4 kbps) or an external user modem. This makes it possible to organize up to 4 channels of intermadal exchange.
In the tract of receiving AVTS-CH (AVTS-C), a semi-automatic correction of the frequency response of the residual attenuation of each channel is provided.
Each telephone channel AVC has the ability to enable the compander.

Cell telephone automation	AVTS-CH (AVTS-C) contains built-in devices for automatic connecting subscribers (telephone automata) that allow the connection:
If the channel is used to transmit data, the telephone automatic cell is replaced by the CF519C built-in modem cell.	StF / CF519C Modems Cell

In AVTS-NC and AVTS-C, there is a control unit, which, using the service modem of each channel (the transfer rate of 100, the average frequency of 3.6 kHz) transmits commands and continuous control of the availability of communication between local and remote terminals. If the connection is disappeared, the audio signal is issued and the contact of the contacts of the external alarm relay. In the non-volatile memory memory, the event log is maintained (enable / disable and the readiness of the equipment, the "disappearance" of the communication channel, etc.) on 512 entries.

The necessary ACC modes are set using the remote control panel or external computer connected via the RS-232 interface to the control unit. The remote control allows the diagram of the levels and the characteristics of the residual damping channel, perform the necessary correction of frequency response and estimate the level of characteristic distortions of the built-in telemechanics modems.

The operating frequency of the equipment can be rebuilt by the user within one of the subbands: 36-125, 125-500 and 500-1000 kHz. Perestroika step - 1 kHz .

Communication Channel Organization Schemes

In addition to the direct communication channel ("point-to-point"), more complex circuits for organizing communication channels (type "Star" are possible between the AVC semi-complexes. Thus, a two-channel dispatching semi-complex allows you to organize a link with two single-channel semi-plates installed in controlled points, and four-channel - with two two-channel or four single-channel semi-plates.

Other similar communication channel configurations are possible. With the help of an additional terminal AVTS-RF, the instrument provides the organization of a four-wire rush without selecting channels.

In addition, the following possibilities may be provided:

	Using only the AVC-HF terminal, work is organized in conjunction with an external modem having a band 4, 8, 12 or 16 kHz in the range of nominal frequencies from 0 to 80 kHz, which allows you to create digital high-frequency communication complexes. For example, on the basis of the Avts-RF and M-ASP-PG-LEP modems, ZELAX modems can be organized with the data transfer rate of up to 80 kbps in a 12 kHz strip and up to 24 kbps in a 4 kHz strip.
	In the nominal band of 16 kHz, two channels are organized in AVC, namely the 1st with a 4 kHz band for telephone and the 2nd with a 12 kHz strip to transmit data to the user's instrument.
	It is organized to work up to four Single-channel subscriber semi-plates of AVC on controlled paragraphs with a single-channel dispatching semi-complex AVC. With a telephone channel band 0.3-2.4 kHz, the instrument will provide one duplex communication channel for the exchange of telemechanical information at a rate of 100 bodes between the dispatch and each semi-complex on the controlled paragraph. When using external modems with a speed of more than 100 bodes, only cyclic or sporadic exchange of telemechanical information between the dispatch and subscriber semi-plates is possible.

Majorbaric parameters of equipment

Name	Depth, mm.	Height, mm.

Installation

The equipment can be installed on the rack (up to several vertical rows), in the 19 "rack or fixed on the wall. All cables for external connections are connected in front. For a separate order, an intermediate terminal bar is supplied to connect cables.

Environmental conditions

The WCC is intended for continuous round-the-clock work in stationary conditions, in closed rooms without permanent service personnel at a temperature of from 0 to + 45c about and relative humidity up to 85%. The performance of the equipment is maintained at ambient temperature to -25С O.

Moscow, May 11 - RIA Novosti. In the book of Vladimir Bogomolov, "The Moment of Truth" about the Great Patriotic War often mentioned "Notes on HF" and the HF communications devices, according to which the Supreme Commander associated with headquarters. The connection was protected, and it was impossible to overhear without the use of special means. What was it for the type of communication?

"HF-Communication", "Kremlinvka", ATS-1 - a system of protected communication channels, which to this day ensures the stability and confidentiality of negotiations of state leaders, ministries, strategic enterprises. Defense methods have become more complicated and improved, but the task remained unchanged: to take care of the state level conversations from foreign ears.

During the Great Patriotic War, according to Marshal I.Kh. Baghamya, "no significant military action began and did not begin and did not begin. The HF communications played an exceptional role as a means of managing troops and facilitated the implementation of combat operations." She was provided not only to the headquarters, but also command directly on the advanced lines, at the sentiments, bridgeheads. Already on the outcome of the war, the most brief contribution of government communications in victory was characterized by the famous Marshal K.K. Rokossovsky: "The use of funds of government communications during the war years made a revolution in the management of troops."

The basis of the government bond appeared in the 1930s, the principle of high-frequency (HF) telephony was laid. It allows you to transfer the human voice, "transferred" to higher frequencies, making it inaccessible to direct listening and allowing the ability to transfer several negotiations on one wire.
The first experiments with the introduction of high-frequency multichannel telephony were conducted from 1921 at the Moscow Plant "Electrosvyaz" under the leadership of V.M. Lebedev. In 1923, a scientist P.V. Shmakov completed experiments on the simultaneous transmission of two telephone negotiations at high frequencies and one at a low frequency on a cable line with a length of 10 km.
A scientist, Professor Pavel Andreevich Azbukin, contributed to the development of high-frequency telephone telephone communications. Under his leadership in 1925, the first domestic equipment of the RF communications was developed on the Leningrad Scientific and Testing Station, which could be used on copper telephone wires.

To understand the principle of telephone HF communications, recall that the usual human voice produces air fluctuations in the frequency band of 300-3200 Hz, and therefore, to transmit sound on a regular telephone channel, a highlighted band is required ranging from 0 to 4 kHz, where sound oscillations will be converted in electromagnetic. You can listen to a telephone conversation on a simple telephone line by simply by connecting the telephone, handset or speaker to the wire. But you can start the wire by a higher frequency band, significantly exceeding the voice frequency - from 10 kHz and above.

This will be the so-called bearing signal. And then the oscillations arising from the human voice can be "hideing" in changing its characteristics - frequencies, amplitudes, phases. These changes of the carrier signal will transmit the sound of the human voice, forming a envelope signal. Attempts to overhear the conversation, connecting to the line by a simple telephone, without a special device will not work - only the high-frequency signal will be heard.
The first lines of government RF communications were extended from Moscow to Kharkov and Leningrad in 1930 and soon the technology has spread throughout the country. By mid-1941, the GF-Communications network included 116 stations, 20 objects, 40 broadcast points and served about 600 subscribers. The work of the engineers of that time also allowed to launch the first automatic station of Moscow in 1930, which later worked for 68 years.

During the Great Patriotic War, Moscow has not remained without a telephone connection. MGTS Museum Workers have shown unique exhibits that were provided in difficult years an uninterrupted message.

At that time, scientists and engineers solved the tasks of improving the protection of communication lines and at the same time the development of complex encryption equipment. The developed encryption systems were very high and in assessing the leadership of the army largely ensured the success of military operations. Marshal G.K. Zhukov noted: "Good work of encrypters helped win more than one battle." Marshal A.M. adhered to a similar opinion Vasilevsky: "No report on the prepared military-strategic operations of our army has become the property of fascist exploration."