Section III Checking and setting up telegraph channels and equipment. Device for measuring distortions of telegraph parcels The product includes

Ministry of Science and Education of the Republic of Kazakhstan

Multidisciplinary College

North Kazakhstan State University

named after academician M. Kozybaev

On the topic “Instruments for measuring distortion”

Completed by: students gr. RES-k-09

Reshetov I.I., Bakutin I.A.

Checked by: teacher

Mikhailov A.N.

Petropavlovsk, 2011

Distortions in telegraph channels, standards for them……………………………3

Checking and setting up telegraph channels and equipment…………………..8

Tactical and technical characteristics of ETI-69……………………………..11

Methodology for measuring distortions in telegraph channels………………………15

Conclusion……………………………………………………………………17

Distortions in telegraph channels, standards for them

Discrete signals transmitted through circuits and communication channels are subject to distortion and various types of interference, as a result of which received pulses may differ from transmitted ones in shape, duration and polarity.

The shape of the received pulse can be easily restored using, for example, a relay, a trigger and similar elements. However, the process of restoring the shape may be accompanied by an additional change in the duration of the received pulse, since these elements have a finite sensitivity (operation threshold).

With the correct response threshold ln of the relay element, the pulses are recorded without distortion and are only shifted relative to those transmitted for a time (Fig. 37a). Shifting the response threshold leads to a change in the duration of the recorded pulse. An increase in the threshold entails a shortening of the current pulses (Fig. 37b), and a decrease in the threshold leads to their lengthening (Fig. 37c).

A change in the duration of received pulses is usually called edge distortion, which manifests itself in the lengthening or shortening of a given pulse due to the corresponding shortening or lengthening of adjacent messages.

The shortening of a burst can reach such a value (shaded part) that it will not be recorded by the recording element, and instead of, for example, a current burst and the following non-current bursts with a duration of each td, one current burst with a duration of 2td will be recorded. Thus, an error may occur when receiving a pulse, which is called a pulse error. The latter can lead to a sign error when, instead of the transmitted combination of one message character, another character is recorded (for example, in the figure, instead of the combination IOII, IIII is recorded).

An error can also occur in another way (Fig. 38), for example, when the sending is exposed to strong interference of sufficient duration and opposite polarity. Distortions, called crushing distortions, occur if the duration of such interference is tdr<

Thus, errors in reception and distortion of pulses are caused by various manifestations of the same interfering causes present in the channel.

During operation, the main parameters to be monitored are reliability and edge distortion.

Reliability is quantified through error rates for single elements and alphabetic characters. It is a generalized parameter characterizing the quality of transmitted information. Acceptable error rate limits are set depending on the transmission speed.

Indirectly, reliability is determined by edge distortions. Although there is no one-to-one correspondence between edge distortions and an error (incorrectly received symbol), it can be said with a high degree of probability that errors will appear when edge distortions exceed the permissible norm.

According to their properties, edge distortions are usually divided into three groups: dominance distortions (n), characteristic (x) and random (c) distortions. This does not take into account the distortions introduced by the transmitting and receiving devices of the terminal equipment.

A feature of dominance distortions is the constancy of their magnitude and sign over time. They can be eliminated by making appropriate adjustments to the receiving device when tuning the channel. A feature of characteristic distortions is the dependence of their magnitude on the nature of the transmitted pulse sequence. These distortions are determined by transient processes in communication channels and circuits.

The magnitude of random distortions, usually caused by interference, is random and varies over time according to various laws. It should be noted that, in a strict sense, characteristic distortions of dominance also arise by chance. However, they can always be eliminated with appropriate adjustments.

In a discrete channel, the relative degree of its own isochronous (synchronous) and start-stop distortions is normalized. Depending on the number of simple channels at the nominal transmission rate, distortion should not exceed the values ​​​​specified in Table 6.

For switched channels, you should be guided by the permissible norm for one simple channel, and for non-switched channels - the norm for seven simple channels.

Table 6.

When transmitting discrete signals at speeds of 200, 600, 1200 baud over PM channels, relative individual distortions should not exceed 20, 30, 35%, respectively, for switched and non-switched channels.

Distortions introduced by switching devices should not exceed 2%, and by the telegraph apparatus transmitter during manual and automatic operation - 5% when setting up the device and 8% during operation.
Checking and setting up telegraph channels and equipment

To eliminate distortions at various stages of the operation of the telegraph communication system, testing and adjustment work is carried out.

At the stage of deployment and preparation for operation, the functionality of the equipment is checked and adjusted.

The basis for testing the functionality of equipment is the principle of testing “by yourself”. In this case, the output of the equipment transmission path is connected to the input of the reception path. Test signals are supplied to the input of the tested TG channel of the equipment, which pass along the transmission path, and then along the reception path they arrive at the output of the channel. The performance of the equipment is judged by the presence and degree of distortion of these signals at the channel output. Thus, the functionality of all equipment units, point sensors and control devices is checked.

The equipment is adjusted using built-in devices, and the following is carried out:

Adjustment of current in telegraph circuits for transmission and reception of each channel;

Adjusting channels to neutral operation

After this, the telegraph equipment is switched on to the TC channel and telegraph channels are set up with the correspondent. In this case, the PM channel allocated for compaction by TT equipment must be checked for residual attenuation and the necessary reception and transmission levels must be established. If the connections are unstable, you should check the telephone channel according to the amplitude characteristics and frequency attenuation characteristics. In some cases, measurements of the magnitude of nonlinear distortions can be carried out.

Methods for checking and setting up PM channels are discussed in the course “Military Field Multichannel Transmission Systems”.

The TT channels are configured simultaneously in both directions. Channels are adjusted to neutral operation based on test signals sent to the channel from the opposite station. A 1:1 test signal (“dots”) is transmitted through other channels not used for information transmission.

To fully check the channel in the forward and reverse directions, a DC loop is installed at the opposite station by connecting the receiving and transmitting sockets of the channel being tested.

Loop testing of all telegraph channels can be done by connecting the output of the telephone channel to its input at the opposite station.

The adjusted channel is put into operation in the telegraph equipment room at the terminal telegraph devices (telegraph devices). At the same time, the OTU must be checked and configured by this time.

Mechanics check and, if necessary, adjust the voltage in the TG transmission and reception circuits and the correctness of their connection.

After entering into communication, the mechanics of the TG stations check the correctness of the control text.

During operation, visual monitoring of the optical signaling is carried out, as well as periodic measurement of current voltages and levels at control points.

For more complete adjustment of telegraph channels and equipment with determination of the amount of distortion, TG signal distortion meters are used, for example, ETI-69, ETI-64, IK-ZU-1, IK-1U. These devices include a test signal sensor and an IKI edge distortion meter.
Performance characteristics of ETI-69

Purpose:

The ETI-69 device is intended for measuring distortions of telegraph parcels, testing telegraph channels, equipment and relays.

The device provides measurement of distortions of telegraph messages in start-stop mode at fixed speeds of 50, 75, 100, 150, 203 baud.

The device provides for measuring distortions of telegraph messages in start-stop mode with smooth speed adjustment.

The device allows you to measure distortions of telegraph messages in synchronous mode, as well as in duration measurement mode in a smooth speed range from 44 to 112 Baud and with the ability to smoothly adjust speeds 150, 200, 300 Baud in the range from +12 to -12%.

The deviation of fixed speed ratings in start-stop mode does not exceed ±0.2% at normal temperatures, ±0.5% at extreme operating temperatures.

The device uses a discrete method of counting the measured value of edge distortion through 2% within the entire elementary frame at all speeds and through 1% within half of the elementary frame. The distortion value is counted according to the displayed numbers from 0 to ± 25% with the possibility of increasing the division value and measurement limit by 2 times.

The error of the measuring part when measuring distortions from its own sensor at speeds up to 200 Baud when reading every 2% does not exceed ±2%, when reading every 1% - ±1%; at speeds of 200 and 300 Baud, this error is ± 3% when reading every 2% and ± 2% when reading every 1%.

The operational error of the device in synchronous mode when receiving from the sensor of another device during a measurement session corresponding to the transmission of 1000 elementary parcels, at a telegraph speed of 50 baud when counting through 2% does not exceed ±3%, and when counting through 1 % - ±2%.

The device records the value of general or start-stop distortions or their maximum value during a measurement session.

The device provides measurement of distortions of the fronts of each of the start-stop cycle messages.

The device allows you to divide distortions into random, characteristic and predominant ones with determination of their sign.

The input device of the device provides reception at speeds up to 100 Baud of rectangular and rounded parcels in single-pole mode and reception of bipolar parcels at all speeds. The minimum current of the input device in double-pole mode is 2 mA, in single-pole mode 5 mA.

The input device of the device is symmetrical and provides the possibility of parallel and serial connection to the measured circuit at the following gradations of input resistance: 25, 10, 3, 1 and 0.1 k0m. The input device is designed for the use of linear voltages in the tested circuits up to 130V in single-pole mode and up to ±80V in bipolar mode.

The test signal sensor of the device produces the following types of signals:

Press "+";

Pressing "-";

- “1:1” (dots);

The text of “Ры” according to international code No. 2, as well as the combinations of “Р” and “У” separately;

Automatically alternating combinations "5:1"

The error of the bipolar messages generated by the device does not exceed 1%.

The sensor produces single-pole signals with a voltage of 120 ± 30 V and two-pole signals with ±60 ± 15 V at a load current of 0 to 50 mA, as well as single-pole and double-pole signals with a voltage of 20 + 6-8 V at a load current of 0 to 25 mA. The output impedance of the device is no more than 200 Ohms.

The device sensor also operates in breaker mode when connected to the output terminals of the device with a load with an external source of line voltage up to 130 V.

The device sensor has overload protection, short circuit alarms and protection against polarity changes of linear power supplies.

The device provides the ability to introduce distortion into the signals of its own sensor up to 95%, as well as an external sensor within the range of up to 92% - in steps of 10 and 1%.

The introduced distortions are distortions of the predominance type with manual installation of any of their signs, as well as with automatic change of the predominance sign up to ±89% within the duration of the start-stop cycle up to ±50%.

The device provides a performance check in the “ON YOURSELF” mode.

A device with a relay testing unit allows you to check and adjust the neutrality, recoil and bounce of telegraph relays of the RP-3 type

Checking the neutrality and return of the relay is carried out with rectangular bursts in operating, test and dynamic modes.

The device is powered from an alternating current network of 127+13-25 V or 220+22-44 V, with a frequency of 50 Hz.

The ETI-69 device is intended for measuring distortions of telegraph messages, testing telegraph channels, equipment and relays.

Technical characteristics of ETI-69:

The device provides measurement of distortions of telegraph messages in start-stop mode at fixed speeds of 50, 75, 100, 150, 203 baud. The device provides for measuring distortions of telegraph messages in start-stop mode with smooth speed adjustment.
The device allows you to measure distortions of telegraph messages in synchronous mode, as well as in duration measurement mode in a smooth speed range from 44 to 112 Baud and with the ability to smoothly adjust speeds 150, 200, 300 Baud in the range from +12 to -12%.

The deviation of fixed speed ratings in start-stop mode does not exceed ±0.2% at normal temperatures, ±0.5% at extreme operating temperatures. The device uses a discrete method of counting the measured value of edge distortion through 2% within the entire elementary frame at all speeds and through 1% within half of the elementary frame. The distortion value is calculated using the displayed numbers from 0 to ± 25% with the possibility of increasing the division value and measurement limit by 2 times.
The error of the measuring part when measuring distortions from its own sensor at speeds up to 200 Baud when reading every 2% does not exceed ±2%, when reading every 1% - ±1%; at speeds of 200 and 300 Baud, this error is ± 3% when reading every 2% and ± 2% when reading every 1%.
The operational error of the device in synchronous mode when receiving from the sensor of another device during a measurement session corresponding to the transmission of 1000 elementary parcels, at a telegraph speed of 50 baud when counting after 2% does not exceed ±3%, and when counting through 1% - ±2%.
The device records the value of general or start-stop distortions or their maximum value during a measurement session. The device provides measurement of distortions of the fronts of each of the start-stop cycle messages. The device allows you to divide distortions into random, characteristic and predominant with determination of their sign.
The input device of the device provides reception at speeds up to 100 Baud of rectangular and rounded parcels in single-pole mode and reception of bipolar parcels at all speeds. The minimum current of the input device in double-pole mode is 2 mA, in single-pole mode 5 mA.

The input device of the device is symmetrical and provides the possibility of parallel and serial connection to the measured circuit at the following gradations of input resistance: 25, 10, 3, 1 and 0.1 k0m. The input device is designed for the use of linear voltages in the tested circuits up to 130V in single-pole mode and up to ±80V in bipolar mode.

The device's test signal sensor produces the following types of signals:
- press “+”;
- press “-”;
- “1:1” (dots);
- “6:1”;
- “1:6”;
- text “Ры” according to international code No. 2, as well as combinations of “Р” and “И” separately;
- automatically alternating combinations “5:1”

The error of the bipolar messages generated by the device does not exceed 1%. The sensor produces single-pole signals with a voltage of 120 ± 30 V and two-pole signals with a voltage of ±60 ± 15 V at a load current of 0 to 50 mA, as well as single-pole and double-pole signals with a voltage of 20 + 6-8 V at a load current of 0 to 25 mA. The output impedance of the device is no more than 200 Ohms.

The device sensor also operates in breaker mode when connected to the output terminals of the device with a load with an external source of line voltage up to 130 V.
The device sensor has overload protection, short circuit alarm and protection against polarity changes of linear power supplies.

The device provides the ability to introduce distortion into the signals of its own sensor up to 95%, as well as an external sensor within the range of up to 92% - in steps of 10 and 1%.

The introduced distortions are distortions of the dominance type with manual installation of any of their signs, as well as with automatic change of the dominance sign up to ±89% within the duration of the start-stop cycle up to ±50%.

The device provides a performance test in the “ON YOURSELF” mode. The device with a relay testing unit allows you to check and adjust the neutrality, recoil and bounce of telegraph relays of the RP-3 type. The neutrality and return of the relay are checked using rectangular bursts in operating, test and dynamic modes.

The device is powered from an alternating current network of 127+13-25 V or 220+22-44 V, with a frequency of 50 Hz.
The power consumed by the device at the rated mains voltage does not exceed 100 VA.

Overall dimensions of the device are 220x335x420 mm. Weight no more than 21 kg.
Overall dimensions of the BIR block are 225x130x125 mm. Weight 1.6 kg.

The operating temperature range of the device is from -10 to +50°C.

You can buy a device from storage ETI-69 (for measuring distortions of telegraph parcels, testing telegraph channels, equipment and relays) at the factory price by placing an online order on the website, or by contacting the company’s managers. Delivery to all regions of Russia and the Republic of Kazakhstan.

STATE STANDARD OF THE UNION OF USSR

TRANSMITTING AND RECEIVING EQUIPMENT
TELEGRAPH CHANNELS
RADIO COMMUNICATIONS

BASIC PARAMETERS, GENERAL TECHNICAL REQUIREMENTS
AND METHODS FOR MEASUREMENT OF THE TRANSMITTER-RECEIVER PATH

GOST 14662-83

(ST SEV 4679-84)

USSR STATE COMMITTEE ON STANDARDS

STATE STANDARD OF THE USSR UNION

By Decree of the USSR State Committee on Standards dated October 10, 1983 No. 4898, the validity period was established

from 01.01.85

until 01.01.90

Failure to comply with the standard is punishable by law

This standard applies to exciters, transmitters and receivers that are part of telegraph radio communication channels of the hectometer and decameter wavelength ranges, operated in stationary conditions.

The standard establishes the basic parameters, technical requirements and methods for measuring the transmitting and receiving path of equipment.

The standard fully complies with ST SEV 4679-84.

1. MAIN PARAMETERS

Notes e. A - start signal of the start-stop device;

Z - table signal of the start-stop device;

B - pressing;

Y - push-up;

(1) - in a wired circuit;

(2) - in the radio channel.

Notes:

3. METHODS OF MEASUREMENT

The pathogen is installed in the radiation class F1B or F7B mode. From a DC voltage source, a voltage of 10 - 25 V is applied to the input of the manipulator and the value of the input current is measured. Input impedance R in is determined by the formula

Where U in - input voltage, V;

First, set the type of operation on the signal generator that corresponds to the radiation class being tested (F1B, F7B or G1B) and tune it to the receiver tuning frequency.

On the low frequency generator (hereinafter referred to as LF), a frequency equal to the baud rate is set, and an output voltage of 15 V is supplied to trigger the test signal sensor. When making measurements on the sensor, the corresponding duty cycles are set for the equipment radiation classes:

F1B - 1:1, 1:2, 1:3, 1:6, 6:1, 3:1, 2:1;

F7B - along the measured channel - |1: 1|1: 1|1: 3|1: 6|1: 6|6: 1|6: 1|3:1|2: 1|

on an unmeasured channel - |1: 1|1: 6|1: 6|2: 1|3: 1|1: 2|1: 3|6: 1|6: 1|

G1B - 1:3, 1:6, 6:1, 3:1.

It is also possible to use a recurrent sequence of 511 sensor pulses.

The output of the test signal sensor should be connected to the external trigger input of the signal generator. The manipulated signal from the signal generator is fed to the receiver and the edge distortion of the receiver's output signal is measured. In this case, the signal level at the receiver input should be 20 dB greater than the sensitivity of the receiver.

(Changed edition, Amendment No. 1).

Pre-installation of generators is carried out in accordance with the requirements of paragraph. From the low-frequency generator, the voltage is supplied simultaneously to the rectangular signal sensor to generate an information signal and to the attachment to form a circular scan of the oscilloscope.

The signal whose edge distortion is measured is fed to the signal input of the set-top box.

Edge distortion is measured using a transparent circular scale with one hundred radial divisions and superimposed on the oscilloscope screen.

With a duty cycle of 1:1, the oscilloscope scale is rotated so that its zero is located in the middle between the brightness marks of the leading and trailing edges of the measured pulses. By setting the specified duty cycle on the pulse sensor in accordance with the requirements of paragraph, the greatest deviation from zero of the brightness mark in any direction is counted by scale divisions. One scale division corresponds to 1% edge distortion.

Rectangular pulses from the test signal sensor are fed simultaneously to the external trigger jack of the signal generator and to the external trigger input of the oscilloscope. The output signal from the receiver is fed to the input of the oscilloscope. Before starting measurements, calibrate the oscilloscope.

With a duty cycle of 1:1, the pulse image is stretched by the sweep duration knobs of the oscilloscope within the extreme marks of the linear part of the scale.

The reference pulse duration is taken to be the average value between the durations of the positive and negative half-waves of the signal (the half-waves are observed when the oscilloscope synchronization switch is switched to the “+” and “-” positions). After this, the leading edge of the positive pulse is set to the zero mark of the scale (the average vertical line of the scale).

By horizontally moving the beam on the oscilloscope, the leading and trailing edges are set at the same distance from the zero mark of the scale and then telegraph distortions are counted from it in any direction according to the maximum deviation from the middle.

APPENDIX 1

Explanation

Telegraph radio communication

Classes of radio emissions:

Frequency telegraphy without the use of a modulating subcarrier with one information channel

F1B (F1)

F7B (F6)

Frequency telegraphy with two or more channels of information

G1 B (F9)

Phase modulation with one channel of information without the use of a modulating subcarrier

Frequency Shift Keying

Dual frequency telegraphy

Telegraphy via frequency shift keying, in which each of the four possible signals corresponding to two telegraph channels is represented by a separate frequency

Relative phase shift keying

Wiring speed

Index manipulation

Ratio of frequency shift in hertz to baud rate

Edge distortion

The largest absolute value of the discrepancy between significant moments and significant intervals and ideal significant moments and significant intervals, respectively

(Changed edition, Amendment No. 1).

APPENDIX 2

Device characteristics

Norm

High frequency signal generator

Frequency range, MHz

0,1 - 200

Output resistance, Ohm

75, 50

± 1

Output voltage at 75 Ohm load, µV

1 - 1 × 10 6

Types of modulation

F1 B, F7B, G1B

Level of spurious emissions, dB, no more

Low frequency signal generator

Frequency range, kHz

0,05 - 20

Frequency setting error, %, no more

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Ministry of Science and Education of the Republic of Kazakhstan

Multidisciplinary College

North Kazakhstan State University

named after academician M. Kozybaev

Abstract

On the topic “Instruments for measuring distortion”

Distortions in telegraph channels, standards for them

Checking and setting up telegraph channels and equipment

Performance characteristics of ETI-69

Methodology for measuring distortions in telegraph channels

Conclusion

Distortions in telegraph channels, standards for them

telegraph channel distortion

Discrete signals transmitted through circuits and communication channels are subject to distortion and various types of interference, as a result of which received pulses may differ from transmitted ones in shape, duration and polarity.

The shape of the received pulse can be easily restored using, for example, a relay, a trigger and similar elements. However, the process of restoring the shape may be accompanied by an additional change in the duration of the received pulse, since these elements have a finite sensitivity (operation threshold).

With the correct response threshold ln of the relay element, the pulses are recorded without distortion and are only shifted relative to those transmitted for a time (Fig. 37a). Shifting the response threshold leads to a change in the duration of the recorded pulse. An increase in the threshold entails a shortening of the current pulses (Fig. 37b), and a decrease in the threshold leads to their lengthening (Fig. 37c).

A change in the duration of received pulses is usually called edge distortion, which manifests itself in the lengthening or shortening of a given pulse due to the corresponding shortening or lengthening of adjacent messages.

The shortening of a burst can reach such a value (shaded part) that it will not be recorded by the recording element, and instead of, for example, a current burst and the following non-current bursts with a duration of each td, one current burst with a duration of 2td will be recorded. Thus, an error may occur when receiving a pulse, which is called a pulse error. The latter can lead to a sign error when, instead of the transmitted combination of one message character, another character is recorded (for example, in the figure, instead of the combination IOII, IIII is recorded).

An error can also occur in another way (Fig. 38), for example, when the sending is exposed to strong interference of sufficient duration and opposite polarity. Distortions, called crushing distortions, occur if the duration of such interference is tdr<

Thus, errors in reception and distortion of pulses are caused by various manifestations of the same interfering causes present in the channel.

During operation, the main parameters to be monitored are reliability and edge distortion.

Reliability is quantified through error rates for single elements and alphabetic characters. It is a generalized parameter characterizing the quality of transmitted information. Acceptable error rate limits are set depending on the transmission speed.

Indirectly, reliability is determined by edge distortions. Although there is no one-to-one correspondence between edge distortions and an error (incorrectly received symbol), it can be said with a high degree of probability that errors will appear when edge distortions exceed the permissible norm.

According to their properties, edge distortions are usually divided into three groups: dominance distortions (n), characteristic (x) and random (c) distortions. This does not take into account the distortions introduced by the transmitting and receiving devices of the terminal equipment.

A feature of dominance distortions is the constancy of their magnitude and sign over time. They are eliminated by appropriate adjustments of the receiving device when tuning the channel. A feature of characteristic distortions is the dependence of their magnitude on the nature of the transmitted pulse sequence. These distortions are determined by transient processes in communication channels and circuits.

The magnitude of random distortions, usually caused by interference, is random and varies over time according to various laws. It should be noted that, in a strict sense, characteristic distortions of dominance also arise by chance. However, they can always be eliminated with appropriate adjustments.

In a discrete channel, the relative degree of its own isochronous (synchronous) and start-stop distortions is normalized. Depending on the number of simple channels at the nominal transmission rate, distortion should not exceed the values ​​​​specified in Table 6.

For switched channels, you should be guided by the permissible norm for one simple channel, and for non-switched channels - the norm for seven simple channels.

Table 6

Number of simple channels	Permissible relative degree of edge distortion
	Isochronous (synchronous)	start-stop

When transmitting discrete signals at speeds of 200, 600, 1200 baud over PM channels, relative individual distortions should not exceed 20, 30, 35%, respectively, for switched and non-switched channels.

Distortions introduced by switching devices should not exceed 2%, and by the telegraph apparatus transmitter during manual and automatic operation - 5% when setting up the device and 8% during operation.

Checking and setting up telegraph channels and equipment

To eliminate distortions at various stages of the operation of the telegraph communication system, testing and adjustment work is carried out.

At the stage of deployment and preparation for operation, the functionality of the equipment is checked and adjusted.

The basis for testing the functionality of equipment is the principle of testing “by yourself”. In this case, the output of the equipment transmission path is connected to the input of the reception path. Test signals are supplied to the input of the tested TG channel of the equipment, which pass along the transmission path, and then along the reception path they arrive at the output of the channel. The performance of the equipment is judged by the presence and degree of distortion of these signals at the channel output. Thus, the functionality of all equipment units, point sensors and control devices is checked.

The equipment is adjusted using built-in devices, and the following is carried out:

- regulation of current in telegraph circuits for transmission and reception of each channel;

- adjustment of channels to neutral operation

After this, the telegraph equipment is switched on to the TC channel and telegraph channels are set up with the correspondent. In this case, the PM channel allocated for compaction by TT equipment must be checked for residual attenuation and the necessary reception and transmission levels must be established. If the connections are unstable, you should check the telephone channel according to the amplitude characteristics and frequency attenuation characteristics. In some cases, measurements of the magnitude of nonlinear distortions can be carried out.

Methods for checking and setting up PM channels are discussed in the course “Military Multi-Channel Transmission Systems”.

The TT channels are configured simultaneously in both directions. Channels are adjusted to neutral operation based on test signals sent to the channel from the opposite station. A 1:1 test signal (“dots”) is transmitted through other channels not used for information transmission.

To fully check the channel in the forward and reverse directions, a DC loop is installed at the opposite station by connecting the receiving and transmitting sockets of the channel being tested.

Loop testing of all telegraph channels can be done by connecting the output of the telephone channel to its input at the opposite station.

The adjusted channel is put into operation in the telegraph equipment room at the terminal telegraph devices (telegraph devices). At the same time, the OTU must be checked and configured by this time.

Mechanics check and, if necessary, adjust the voltage in the TG transmission and reception circuits and the correctness of their connection.

After entering into communication, the mechanics of the TG stations check the correctness of the control text.

During operation, visual monitoring of the optical signaling is carried out, as well as periodic measurement of current voltages and levels at control points.

For more complete adjustment of telegraph channels and equipment with determination of the amount of distortion, TG signal distortion meters are used, for example, ETI-69, ETI-64, IK-ZU-1, IK-1U. These devices include a test signal sensor and an IKI edge distortion meter.

Performance characteristics of ETI-69

Purpose:

The ETI-69 device is intended for measuring distortions of telegraph messages, testing telegraph channels, equipment and relays.

The device provides measurement of distortions of telegraph messages in start-stop mode at fixed speeds of 50, 75, 100, 150, 203 baud.

The device provides for measuring distortions of telegraph messages in start-stop mode with smooth speed adjustment.

The device allows you to measure distortions of telegraph messages in synchronous mode, as well as in duration measurement mode in a smooth speed range from 44 to 112 Baud and with the ability to smoothly adjust speeds 150, 200, 300 Baud in the range from +12 to --12%.

The deviation of fixed speed ratings in start-stop mode does not exceed ±0.2% at normal temperatures, ±0.5% at extreme operating temperatures.

The device uses a discrete method of counting the measured value of edge distortion through 2% within the entire elementary frame at all speeds and through 1% within half of the elementary frame. The distortion value is calculated using the displayed numbers from 0 to ± 25% with the possibility of increasing the division value and measurement limit by 2 times.

The error of the measuring part when measuring distortions from its own sensor at speeds up to 200 Baud when reading every 2% does not exceed ±2%, when reading every 1% -- ±1%; at speeds of 200 and 300 Baud this error is ± 3% when reading every 2% and ± 2% when reading every 1%.

The operational error of the device in synchronous mode when receiving from the sensor of another device during a measurement session corresponding to the transmission of 1000 elementary parcels, at a telegraph speed of 50 baud when counting after 2% does not exceed ±3%, and when counting through 1% -- ±2% .

The device records the value of general or start-stop distortions or their maximum value during a measurement session.

The device provides measurement of distortions of the fronts of each of the start-stop cycle messages.

The device allows you to divide distortions into random, characteristic and predominant with determination of their sign.

The input device of the device provides reception at speeds up to 100 Baud of rectangular and rounded parcels in single-pole mode and reception of bipolar parcels at all speeds. The minimum current of the input device in double-pole mode is 2 mA, in single-pole mode 5 mA.

The input device of the device is symmetrical and provides the possibility of parallel and serial connection to the measured circuit with the following gradations of input resistance: 25, 10, 3, 1 and 0.1 k0m. The input device is designed for the use of linear voltages in the tested circuits up to 130V in single-pole mode and up to ±80V in bipolar mode.

The device's test signal sensor produces the following types of signals:

-- press “+”;

-- press “--”;

-- “1:1” (dots);

-- "6:1";

-- "1:6";

-- text “Ры” according to international code No. 2, as well as combinations of “Р” and “У” separately;

-- automatically alternating combinations “5:1”

The error of the bipolar messages generated by the device does not exceed 1%.

The sensor produces single-pole signals with a voltage of 120 ± 30 V and two-pole signals with a voltage of ±60 ± 15 V at a load current of 0 to 50 mA, as well as single-pole and double-pole signals with a voltage of 20 + 6-8 V at a load current of 0 to 25 mA. The output impedance of the device is no more than 200 Ohms.

The device sensor also operates in breaker mode when connected to the output terminals of the device with a load with an external source of line voltage up to 130 V.

The device sensor has overload protection, short circuit alarm and protection against polarity changes of linear power supplies.

The device provides the ability to introduce distortion into the signals of its own sensor up to 95%, as well as an external sensor within the range of up to 92% - in steps of 10 and 1%.

The introduced distortions are distortions of the dominance type with manual installation of any of their signs, as well as with automatic change of the dominance sign up to ±89% within the duration of the start-stop cycle up to ±50%.

The device provides a performance test in the “ON YOURSELF” mode.

The device with a relay testing unit allows you to check and adjust the neutrality, recoil and bounce of telegraph relays of the RP-3 type

The neutrality and return of the relay are checked using rectangular bursts in operating, test and dynamic modes.

The device is powered from an alternating current network of 127+13-25 V or 220+22-44 V, with a frequency of 50 Hz.

The power consumed by the device at the rated mains voltage does not exceed 100 VA.

Overall dimensions of the device are 220x335x420 mm. Weight no more than 21 kg.

Overall dimensions of the BIR block are 225X130X125 mm. Weight 1.6 kg.

The operating temperature range of the device is from --10 to +50°С.

Product composition

The product includes:

-- device ETI-69;

-- relay test unit;

-- connecting cords;

-- a set of spare parts;

-- cover of the ETI-69 device;

-- operational documentation

-- storage box.

Methodology for measuring distortions in telegraph channels

The measurement is carried out in a four-wire, double-pole mode of telegraph outputs at a line voltage of 20V, input resistance of 1 kOhm, CHANNEL mode. The distortion device of the device in channel mode is included in the receiving part, its regulator must be set to position 0. The measuring device is connected to the switching sockets to which the inputs (outputs) of telegraph channels are connected. The terminal telegraph equipment is turned off. From the distortion meter sensor, a pressing signal “+” is sent to the telegraph channel, then “-”. When changing the polarity of the currents, it is necessary to make sure that the milliapermeter needle of the distortion meter deviates in the appropriate direction and by approximately the same amount. Having received the “+” and “-” presses from the opposite station and thus ensured that a telegraph communication channel is available, you should adjust the telegraph channel to a minimum of dominance. To do this, set the switches of the distortion meter to the CHANNEL 1:1 position, the nominal speed for this channel, DURATION, WITHOUT MEMORIZING.

If there is a constant predominance of values ​​in the channel, the values ​​of the displayed numbers on the right and left sides of the scale will differ significantly. To eliminate this predominance, it is necessary to adjust the REG. CHANNEL potentiometer. telegraph channel to reduce the difference in distortion values ​​on the right and left sides of the scale to a minimum. Determine the amount of distortion within 10 seconds.

The degree of synchronous distortion is determined as the sum of the values ​​on the right and left parts of the device.

Switch the device sensor to PI mode and also determine the amount of distortion. There should be practically no differences between the variables in the 1:1 and PI modes. Differences in measurement results indicate increased characteristic distortion in a given channel.

The amount of distortion measured in the telegraph channel should not exceed standard values.

Conclusion

We studied instruments for measuring distortions, such as ETI-69, ETI-64, IK-ZU-1, IK-1U, became familiar with the principles of their operation, consolidated our knowledge of the types of distortions, and learned all the principles of telegraph communication.

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Class 21a 7o5

Subscription group M 86

A. B. Pugach, K. A. Brusilovsky, N. A. Berkman, V. S. Bleichman and S. Yu. Zlkind

DEVICE FOR MEASUREMENT OF TELEGRAPH DISTORTION

Declared on June 3, 196, under Xe 733226/26-9 to the Committee for Inventions and Discoveries under the Council of Ministers of the USSR

There are known devices for measuring distortions of telegraph messages in synchronous and start-stop modes, made on semiconductor devices and ferrites with PPG and including a distributor on two parallel shift registers. The measurement accuracy of such devices is low.

To improve the measurement accuracy, ensure the convenience of reading the distortion value and the independence of the reading from the subjective error of the observer, a device is proposed that uses a matrix circuit of a start-stop discrete indicator on neon lamps.

To ensure a certain duration of reliable ignition and extinguishing of neon lamps, as well as to increase the duration of their burning, the device uses a one-shot transistor, a switch and a storage device made of M cells.

The skeletal diagram of a discrete-action start-stop-synchronous distortion meter is shown in the drawing.

The device contains a clock pulse generator 1, an input device 2, a storage device 3, a distributor for M outputs, made in the form of two parallel shift registers 4 and 5, key devices b and 7, a matching circuit 8, an amplifier 9, a storage device 10, and shaping devices 11, indicator 12, shift register 18 and switch 14. The specified distortion meter nodes are made on semiconductors and ferrites with a rectangular hysteresis loop. The indicator is made using neon lamps. The distortion on the indicator is measured by the combustion of neon lamps arranged in the form of a matrix consisting of M vertical buses. The scale division price is 100 lv.”

In synchronous operation mode, one horizontal matrix is ​​used.

In the start-stop operating mode, it is possible to measure the distortions of each elementary parcel.

For this purpose, the matrix contains six horizontal lines, each of which corresponds to the serial number of the studied parcels of the start-stop combination.

The telegraph parcels under study arrive at the input device 2, which converts the incoming rectangular signals into a sequence of short pulses corresponding to the characteristic recovery moments (CHM) of the incoming parcels, synchronized with the clock pulses of the generator 1. Each CMT following the start transition is recorded in the memory device 8.

When the pulse coming from the output of device 8 and the distributor pulse (registers 4 and 5) coincide in time, a signal is generated that is supplied to the corresponding element of the drive 10 through the key device 7. Thus, the CMV is fixed in the drive 10 depending on its offset from the ideal position.

The number of storage elements corresponds to the scale division of the device. After the CMV offset is recorded in one of the elements of the drive 10, the storage device 8 returns to its original state. After some time, the coincidence circuit 8 is triggered. The amplifier 9 reads information from the drive 10 into the forming circuit 11 and advances the information in register 18. The forming circuit 11 contains X monostables on two semiconductor triodes. Each one-shot device controls a high-voltage semiconductor triode that controls the ignition of the neon indicator lamp. This ensures reliable ignition and extinguishing of the neon lamp.

When measuring in start-stop mode, the distributor is started (registers 4 and 5) by start-stop trigger 15 at the moment the stop-start transition arrives at input device 2. The distributor stops after the passage of six and a half chips. To determine the moment of stopping, register 18 is used, containing seven elements.

The same register is used to control switch 14, which serves to switch the horizontal rows of the indicator matrix. Since the coincidence circuit 8 and the amplifier 9 operate in the middle of the incoming parcels of the old stop combination, the switching of the horizontal rows of the indicator matrix occurs in the middle of the elementary parcels. This allows the measurement process and the indication process to be separated in time. Neon lamps burn for the same amount of time regardless of the amount of distortion.

The described device provides measurement of distortions of telegraph parcels at telegraph speeds up to 1000 baud with a measurement error of up to 2%. The device can be widely used at telegraph stations and in laboratory conditions.

Subject of the invention

1, A device for measuring distortions of telegraph messages in synchronous and start-stop modes, made on semiconductor devices and ferrites with PPG, including a distributor on two parallel shift registers, differing in that, for the purpose

¹)47/97 increasing the measurement accuracy, ensuring the convenience of reading the distortion value and the independence of the reading from the subjective error of the observer, it uses a matrix circuit of a start-stop discrete indicator on neon lamps, consisting of M vertical!

100 - the price of division of the scale and six horizontal bars, at the intersection of which the INDICATOR LAMPS are turned on, each of which corresponds to a certain amount of distortion of the code combination message.

2. The device, 1, differs in that, in order to ensure a certain duration of reliable ignition and extinguishing of neon lamps, as well as increasing their burning duration, it uses a one-shot transistor, supplying control pulses to the vertical buses of the matrix, the switch and the drive of M cells. carrying out switching of six horizontal buses of the matrix and synchronizing the moments of their switching with the corresponding midpoints of the elementary parcels.

Compiled by G. E. Emelyanov

Editor N. S. Kutafina Technical editor A. A Kamyshnikova Proofreader V. Andrianova

Subp. to the stove, 7 VI-62 Paper format. 70; 108 l g Volume 0.26 pg l.

Zach. 6023 Circulation 800 Price 4 kopecks.

CBTI Committee for Inventions and Discoveries under the Council of Ministers of the USSR

Moscow, Center, M. Cherkassky per., 2/6

Printing house CBTI, Moscow, Petrovka, 14