SU873427A1 - Device for measuring communication channel residual attenuation - Google Patents

Description

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The invention relates to communication system monitoring devices and can be used in automated communication channel monitoring systems for measuring the residual attenuation of a through channel.

A device for measuring the residual attenuation of a communication channel is known, which contains a measuring sigjana generator on the transmitting side and a tcowwytator on the receiving side, the signal input and output of which are connected respectively to the forward link path and the threshold input channel. the unit, the input and output of which are connected respectively with the signal and control inputs of switch 1.

However, the known device has a clearly defined measurement boundary, since the measurement process depends on the qualifications of the personnel; ti requires interruption of communication for the measurements.

The aim of the invention is to reduce the measurement time.

For this purpose, 8 a device for measuring the residual attenuation of a communication link containing, on the transmitting side,

the measuring signal generator, and on the receiving side a switch, the signal input and output of which are connected respectively to the output of the forward link and to the input of the reverse channel, communication, and the threshold unit, the input and output of which are connected respectively to the signal and control inputs of the switch ,

10 serially connected generator of sawtooth voltage, amplitude modulator and first reversible counter and series connected

15 an additional threshold unit, an additional switch and a second reversible counter, while the output of the measuring signal generator is connected to the second amplitude input

20 of the modulator, the output of which is connected to the input of the forward channel, and the output of the reverse communication channel is connected to the input of the additional threshold unit and to the second inputs of the additional 25 switch and the first and second reversible counters.

Fig. 1 shows the structural electrical circuit of the proposed device; Fig. 2 - voltage diagrams for the work done.

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The device for measuring the residual attenuation of the communication channel contains on the transmitting side a measuring signal generator 1, a saw-voltage generator 2 connected in series, an amplitude modulator 3 and a first reversible counter 4 and connected in series an additional threshold unit 5, an additional switch 6 and a second roar, A batch counter 7, and on the receiving side a switch 8 and a threshold unit 9, 10 a forward link, 11 a reverse link.

A device for measuring the residual damping of a telecommunication operates as follows.

The generator of the measuring signal 1 continuously outputs the voltage of a certain frequency to the gilplit modulator 3, which is locked in the initial state. When a sawtooth voltage 2 of a sawtooth pulse of fixed duration arrives from the generator at the second input of the amplitude modulator 3, a packet of pulses with a linearly decreasing (increasing) amplitude is formed at its output during the pulse duration of the sawtooth generator 2. This packet of pulses goes to the direct input channel 10. The threshold unit 9 is configured so that in the absence of attenuation in the forward channel 10 through the switch it controls.8 all the pulses of the original series pass, and in the presence of hani — only those pulses whose amplitude is higher than the threshold threshold unit 9. Thus, the number of pulses at the output of switch 8 is inversely proportional to the decay of the forward channel 10. The shortened sequence of pulses at the output of switch 8 (see Fig.26) the reverse channel 11 is fed to the first inputs of the additional switch b and the threshold unit 5 and the reversing counters 4 and 7. At the same time, the second input of the first reversing counter 4 receives the initial pulse train A (Fig. 2o), from which m counter subtracted and truncated series. Thus, the first reversible counter 4 counts n pulses (Fig. 2.1) and its readings are pr; mo is proportional to the attenuation of the b "direct channel 10, which can be determined from the expression

RRR, 1 AND

where LPR is the residual attenuation of the forward channel db1; P - the price of a single pulse series

And Gdbz;

psa-a - readings of the first reversible counter 4;

And - the number of pulses in the original series;

 the number of pulses at the output of the reverse channel. The triggering level of the additional threshold unit 5 is set so that in the absence of attenuation in the reverse channel 11, all the pulses of series a coming to the input of the reverse channel 11 pass through the additional switch B controlled by it, and in the presence of attenuation only the pulses are higher. the threshold of operation of the additional threshold block 5. Received at the output of the additional switch b of series a2 (fng.2c) is fed to the second input of the second reversible counter 7, where it is subtracted from the series a. Thus, the second reversal counter 7 counts n / j pulses (Fig. 26) and its readings are directly proportional to the residual attenuation bpgp of the reverse channel 11, which is determined by the formula

oSf -Pii- 2 where boSP residual attenuation of the return channel Gdb} J PI- the price of one pulse of the series a db,

Io, (c-indications of the second reversible counter 7; the number of pulses at the output of the additional switch 6.

The accuracy of measurements using the proposed device is directly proportional to the pulse duration of the saw-tooth generator, i.e. the number of pulses in the original series, however, the duration of the pulse is advisable to choose no more than 200–300 ms, which will not have a significant effect on the quality of the communication even if it is not necessary to select pauses in speech signals for measurements.

To remove the frequency characteristics of the communication channel, using the proposed device, it is sufficiently stepwise (manually or automatically) to change the frequency of the measuring signal generator in the required range.

The use of the proposed device for measuring the residual attenuation of the communication channel shortens the measurement time compared to a limestone device.

Claims (1)

 Invention Formula A device for measuring the residual attenuation of a communication channel, containing a measuring signal generator on the transmit side, and a switch on the receiving side, the signal input and output of which are connected respectively to the direct output