SU879794A1 - Device for monitoring communication channel - Google Patents

Description

(54) DEVICE FOR THE CONTROL OF A COMMUNICATION CHANNEL

I

 The invention relates to a measurement technique and can be used to assess the quality of communication channels prepared for the transmission of discrete signals.

A device for monitoring a communication channel is known, comprising a sensor on the transmitting side, test signals, and on the receiving side an amplifier, a rectifier, a clock synchronization unit and a block-cycle synchronization unit, combined at the input. , the subtraction unit and the first and second keys, the outputs of which, respectively, through the first and second memory blocks are connected respectively to the first and second inputs of the voltage ratio meter, the output of which is connected to the input of the indicator P.

However, the known device has the lowest accuracy of control.

The purpose of the invention is to improve the accuracy of control.

To do this, the device for monitoring the communication channel, containing on the transmitter side a sensor of test signals, and on. the receiving side — an amplifier, a rectifier, a clock synchronization unit and a cyclic synchronization unit, a subtraction unit and the first and second keys, the outputs of which, respectively, via the first and second memory blocks, respectively, are connected to the first and second inputs of the voltage ratio meter, output which is connected to the input of the indicator, a control unit is inserted, the first fnlter, the trigger and the phase detector and the serially connected carrier frequency generator, the modulator, the second filter , the envelope detector signal, the coding unit and the third memory block, the amplifier output being connected to the combined modulator input, a rectifier input, the output of which is connected to the first fnl input and the phase detector input, the output of which is j connected to the cycle synchronization block input, the output of which is connected to the first input of the control unit, the second input to the first, second, third and fourth outputs of which are connected respectively to the output of the contact synchronization unit. with the second entrance

20 of the encoding unit, with the first input of the first key, with the first input of the second key and with the second input of the third memory block, the first input and output of which are connected respectively to the first and second inputs of the subtraction unit, the output of which is connected to the combined second inputs of the first and second keys.

The drawing shows a structural electrical circuit of the proposed device.

The device for monitoring the communication channel on the transmitting side I of the sensor 2 of the test signals, and on the receiving side 3 of the rectifier 4, the first filter 5, the trigger 6, the phase detector 7, the modulator 8, the carrier generator -frequency 9, the second filter 10, And signal envelope detector, coding unit 12, clock synchronization unit 13, frame alignment unit 14, first memory block 15, control block 16, subtraction block 17, first and second keys 18 and 19, respectively, amplifier 20, second memory block 21 , voltage ratio meter 22, indicator 23, third lock the memory 24, the transmitting and receiving sides 25 associated voice frequency channel (PM).

The device operates as follows: The test signal is a periodic sequence of phase-modulated pulses of duration V. in which the first pulse of the cycle has a double amplitude. The cycle period can be taken arbitrarily, however, when measuring the channels of PM, it is advisable to take it equal to 1 ° 12to. This allows you to control the amplitudes of almost all the signal responses characteristic of the PM channels. If necessary, the number of pulse sequences in the cycle can be increased (reduced) ..

The sensor of the test signals 2 on the transmitting side 1 generates a test sequence of pulses that is transmitted through the PM channel to the receiving side 3. At the receiving side, the signal first passes the amplifier 20, which has gain control, which allows connection to the PM channel with different measuring levels. From the output of the amplifier 20, the signals are fed to the input of the modulator 8 and to the phase detector 7, which converts the phase-modulated sequence and the sequence of binary DC pulses, then fed to the input of the clocks 13 and frame clocks 14, the signals of which ensure the operation of the block, management 16.

For operation of the phase detector 7, a reference oscillation is needed, which is obtained from a signal that passes through rectifier 4, first filter 5 and trigger 6. Modulator 8, powered by carrier oscillator 9i, converts the frequency of the received signal and, together with second filter 10, provides high-frequency filling the received signal, which contributes to a clearer envelope of the signal at the output of the detector by the signal envelope 11.

From the output of the envelope detector signal

The -11 received sequence is fed to the working input of coding unit 12, to the control input of which at the corresponding moments of time clock pulses come from one of the outputs of control unit 16. This ensures coding of amplitude values of the main pulse and responses. The control unit 16, to the input of which clock and cyclic synchronization pulses from blocks 13 and 14 are applied, controls the operation of block 12

the coding, the third memory block 24, and the first and second keys 18 and 19. In determining the D-criterion, the comparison must be made with a pulse whose amplitude is least changed. In the 12 element sequence, this is / 4. This is provided by the memory unit 24, from which the amplitude code value is supplied to the subtraction unit 17, where the amplitudes of the main pulse and responses are compared. The result of the amplitude comparison is sent to the first and

the second keys 18 and 19 and further, in accordance with the pulses of the control unit 16, are fed to the first memory block 15 or to the second memory block 21, where they are summed up. The voltage gauge 22 provides the value of the D-criterion, which is fixed by the indicator 23.

Thus, the choice of a special test signal structure increases the stability of the synchronization system,

which eliminates the need to use the return channel of PM. This gives a significant increase in measurement accuracy and 1.5-2 times less time for assessing the quality of the transmission path of discrete signals, since the use of a similar

the estimator at the other end of the channel allows you to simultaneously measure the reverse transmission path.

Claims (1)

Invention Formula A device for monitoring the communication channel, containing a sensor of test signals on the transmitter side, and an amplifier, a rectifier, a combined clock unit and a frame clock unit, a subtractor unit and the first and second keys at the input. and the second memory blocks are connected respectively to the first and second inputs of the voltage measurement meter, the output of which is connected to the indicator input, characterized in that, in order to increase the control accuracy, a block is inserted control, serially connected first filter, trigger and phase detector and serially connected carrier oscillator, modulator, second filter, signal envelope detector, coding unit and third memory block, with amplifier output connected to combined modulator input, rectifier input the output of which is connected to the input of the first filter and the input of the phase detector, the output of which is connected to the input of the frame synchronization unit, the output of which is connected to the first input: the home of the control unit, the second input and vy, second, third and fourth outputs of which are connected respectively to the clock output unit sinhronizatsi11, with a second input of the coding unit, with the first input of the first key, the first input Vgoru key and a second input of the third memory block, the first input and output koto-; They are connected to the first and second inputs of the subtractor, respectively, the output of which is connected to the combined second inputs of the first and second keys. Sources of information taken into account in the examination. Lev A. Yu. And others. Measurement of readings) 1st impulse response of the St: -: zi channel. Proceedings of educational institutes of communication, vol. 39, L., 1968, p. 97-100 (prototype). etc