SU879789A1 - Device for testing operability of digital communication system video generator - Google Patents

Description

(5) DEVICE FOR MONITORING THE OPERATION CAPACITY OF THE DIGITAL COMMUNICATION SYSTEM VIDEO REGENERATOR

I

The invention relates to communications and can be used in the operation of the equipment of the linear path of digital communication systems.

A device for monitoring the operability of a digital video communication system of a digital communication system, comprising a video regenerator consisting of a series-connected amplifier, a threshold unit, a pulse driver, the output of which is a video regenerator output and connected via an attenuator to one of the adders modulo two, the input threshold of the threshold unit connected to the output of the clock selection unit of the video recorder, in which the output of the amplifier is connected to the input of the clock selection unit and through From the automatic gain control unit (AGC), to the control input of the amplifier, the output of the AGC unit is another output of the video recorder and connected via the first valve to one of the inputs of the adder, and through series-connected inverter and the second valve to the other input of the adder, whose output connected to one of the inputs of the integrator of the malfunction of the malfunction, the other input of the integrator of the malfunction of the malfunction of the malfunction is connected to the output of the modulo-two adder.

However, the known device does not provide the required quality control.

The aim of the invention is to improve the quality of the control.

To do this, an additional threshold unit and an additional valve and a low-pass filter connected in series are introduced into the known device, while the input of the clock selection unit of the video recorder is connected to the signal input of the additional threshold unit, the synchronization input of which is connected to the input of the additional valve. the output of the clock selection unit of the video recorder and the synchronization input of a modulo two modulator, the auxiliary input of which is connected to the output of the additional threshold unit, and the output of the low pass filter is connected to the auxiliary input of the adder. The drawing shows a structural electrical circuit of the proposed device. The device for monitoring the operability of the digital video communications system includes a video recorder 1, consisting of amplifier 2, a threshold unit 3 of the pulse generator A, an AGC unit 5 and a frequency selection unit 6, the first and second valves 7.8, respectively. inverter 9, adder 10 modulo two attenuator 11, adder 12, block 1} of malfunction recording with integrator 1, low-pass filter 15, additional fan 1b and additional threshold block 17. The device works as follows. In case of sudden failure of the video recorder blocks 1, the voltage at the output of the adder 12 changes dramatically and enters the input of the integrator 1 of the block 13. The other input of the integrator 14 of the block 13 receives impulses from the output of the adder 10, the number of which is proportional to the error probability for a certain time interval when transmitting digital signals. The information coming from the output of adder 10 contains a series of intermediate values that are subject to quantization and coding in block 13. This information can be transmitted over the telecontrol channel and used at the service points for estimating and predicting line quality. The information coming from the output of the sum of the matrix 12 can be used to automatically replace the faulty video recorder 1 with a backup one. The monitoring of the failures of the video recorder blocks of the nerator 1 is performed as follows. in a way. In the absence of the input of the video recorder 1 or the output of the amplifier 2 signals at the output of the block 5, the control voltage is zero. Then, a voltage appears at the output of the inverter 9, which passes through the adder 12 and is recorded in block 13 as a fault signal. On exit from block 5, either the maximum signal, the minimum signal or the zero signal appears at its output. Then, at the exit of one of the valves 7 or 8, a signal appears about the output of the video recorder 1. In the event of a malfunction of the threshold unit 3 or the driver k from the output of the attenuator 11, a voltage equal to zero is applied to one of the inputs of the sum tortor 10. The additional input of this same adder 10 receives signals from the output of the additional threshold unit 17- Because in the transmitted sequence There are no pulses at all positions, and at the output of the adder 10 pulses appear, indicating a failure. The corresponding voltage is applied to the output of block 13 and is recorded as a fault. If the block 6 malfunctions, there is no voltage at its output, and no signal is received at the auxiliary input of the adder 12. If block 6 is working, then the auxiliary input of the adder 12 receives the voltage of the block 6 rectified by the additional valve 16 and the filter 15 that has passed the filter 15. When measuring the frequency of failures, the signal from the output of the amplifier 2 is fed simultaneously to the threshold unit 3 and the additional threshold unit 17 having different the thresholds, while the threshold of the threshold unit 3 is chosen optimal from the point of view of minimizing the probability of error at the output of the video recorder 1. In this case, the difference between the failure rates at the outputs of the threshold unit 3 since the additional time traction unit 17 depends on the interference level, i.e. associated with the likelihood of failures at the output of video recorder 1. Totalizer 10 reduces the frequency of failures at the outputs of these blocks, which, after averaging in integrator 14, is recorded in block 13. When fluctuating interference has continuous distribution / probabilities, the frequency of failures is measured during operation, and there is no need. in the use of special measuring signals. The proposed device provides comprehensive monitoring of the performance of the video recorder and allows monitoring the frequency of channel failures without using special measurement signals,

Claims (1)

1. USSR authoring certificate No. 515293, class, Oi B for ZA6, 1976 (prototype).