SU915249A1 - Device for monitoring videoregenerator of digital communication system - Google Patents

Description

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

A device for monitoring a video regenerator of a digital communication system is known. It consists of a series-connected amplifier and a decision block, a clock selection block, whose input is combined with the input of the decision block, and the output is connected to the synchronization input of the decision block, containing the first and second detectors, signal inputs, which are combined, and the outputs are connected to the corresponding inputs of the subtracting unit and the inputs of the adder, the output of which is connected to the input of the registration unit [1].

However, the known device has a low accuracy of control.

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

This goal is achieved by the fact that in the control device of the video recorder digital communication system ,. consisting of a series-connected amplifier and a decision block, a clock selection block, the input of which is combined with the input, a decision block, and the output is connected to the synchronization input of the decision block, containing the first and second detectors, the signal inputs of which are combined, and the outputs are connected to the corresponding inputs subtractive unit and the inputs of the adder, 'the output of which is connected to the input of the registration unit, introduced a differentiation unit, a phase shifter and a Strobe pulse shaper, while the input of the differential unit Itirovaniya combined with the input of the decision block

_ video recorder, and the output is connected

5 to the other combined inputs of the first and second detectors, the gating inputs of which are connected to the corresponding outputs of the gating pulse shaper, the input of the gating device is connected to the output of the phase shifter and the synchronization inputs of the first and second detectors, and control input with output of the subtracting unit.

Moreover, each detector contains, ^ the first and second elements AND, the combined first inputs of which are 30 the signal input of the detector, and

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the second inputs of the elements AND are connected to the corresponding inputs of the detector gating, the output of each of the elements AND is connected through an appropriate memory block to the input of the adder, the output of which is connected to the input of the integrator 5, the output of which is (detector output, combined | the synchronization of the memory blocks are connected to the synchronization input of the detector 10

In addition, each memory block of the detectors contains a short-circuited trigger, the signal one whose input is the input of the memory block and the output connected ^; to the D-flip-flop signal input, input; 15 synchronization of which is connected to the reset input of the short-circuit trigger and is the input of the synchronization of the block of the folder.

Figure 1 presents the structural 20 of the electrical circuit of the device? figure 2 is an embodiment of the detector and the memory block.

The control unit of the video regenerator, the digital communication system 25 contains a video recorder 1 consisting of an amplifier 2, a decisive block 3 and a block 4 for allocating a clock frequency, an adder 5, a block 6 of registration, a block 7 of differentiation, a phase shifter 8, a driver 9 gating pulses, subtracting unit 10, the first and second detectors 11 and 12, respectively, each of which. consists of (figure 2) integrator 13 ,, ,,

the first and second elements And 14 and 15 respectively, the adder 16 and two memory blocks 17 and 18, each of which contains a short-trigger 19

and D-flip-flop 20. _

The device works as follows. ^ 0 way.

The signal to be regenerated is fed to the input of amplifier 2, and then, after amplification, to the input of decision block 3, in which the transmitted signal is restored in form and temporal position. The clock voltage is extracted from the signal in block 4 of the video recorder 1. Due to the presence of noise, and also due to the random nature of the signal, phase fluctuations of the maximum of the regenerated signal relative to the time of gating of the decision block by the clock frequency are observed. Due to the large number of factors on which phase fluctuations depend, the distribution law of these fluctuations is close to normal, and the variance is in.

depends more on the static structure of the signal and the degree of power is determined by the noise in the communication channel.

In the proposed device, a signal characterizing the quality of the regenerator operation is generated by estimating the probability of a maximum signal falling between two points on the time axis. The output of the differentiation unit 7 produces a pulse, the temporary position of which corresponds to the maximum voltage of the signal at the amplifier output. If the pulse is located between the time points corresponding to the front "edges of the gating pulses, then a voltage pulse is generated at the output of the adder 16 of the first detector 11. The average number of such pulses per unit of time corresponds to the probability of phase fluctuations between two time points and is estimated by the detector integrator 13. The larger the fluctuation of fluctuations, the greater the average number of these pulses, the greater the voltage at the integrator output 13, When the signal maximum reaches the zone n the voltage equivalence of the strobes on the output of the adder 16 does not form a voltage pulse. The first and second detectors 11 and 12 work similarly. If their output voltages are not equal, this indicates the presence of a constant component of phase fluctuations. voltage of the difference of the detectors, this constant component is eliminated. Then the voltage values at the output of both detectors are proportional to the variance of the phase fluctuations. The adder 5 allows to increase the accuracy of recording phase fluctuations in case of asymmetrical changes in the parameters of both detectors 11 and 12.

The first and second elements And 14 and 15 produce at the output a signal when the corresponding gates coincide with a pulse at the output of the differentiation unit 7. This signal sets the corresponding short-circuit trigger to the “” state, which is memorized in the corresponding D -trigger. Thus, at the inputs and, accordingly, the output of the adder 16, pulses with a duration equal to the repetition period of the clock pulses will appear, i.e. period of the clock frequency.

Sync pulses should begin after a certain time interval after the end of the gating pulses.

I appropriate detector. In addition to controlling the time at which information is transmitted to the D-trigger, the sync pulse resets the short-circuit trigger to the “O” state, preparing it to receive the information in the next

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time step of the video recorder.

Thus, the advantage of the proposed device is to increase the sensitivity of monitoring the performance of a video recorder with large signal-to-noise ratios (respectively, with greater reliability of transmission, information), reducing the inertia of control, which is achieved by passing from amplitude signal analysis to measuring its phase characteristics, i.e. transition to another dimension.

In addition, the proposed device allows control without introducing redundancy into the transmitted signal, without interrupting the process of transmitting information and without using special measuring signals.

Claims (3)

Claim The control unit of the digital video communication system regenerator, consisting of a series-connected amplifier and a decision unit, a clock frequency selection unit, whose input is combined with the input of the decision unit, and the output is connected to the synchronization input of the decision unit, containing the first and second detectors, the signal inputs of which are combined, and the outputs are connected to the corresponding inputs of the subtracting unit and the inputs of the adder, the output of which is connected to the input of the recording unit, in order to increase the accuracy of control, entered differentiation unit, phase shifter and gating pulse shaper, while the input of the differentiation unit is combined with the input and the output is connected to other combined inputs of the first and second detectors, the gating inputs of which are connected to the corresponding outputs of the gating pulse shaper, whose input is connected to the output of the phase shifter and to the synchronization inputs of the first and second detectors, the signal input of the phase shifter is connected to the output of the selection unit .. the frequency of the video recorder, and the control input - with the output of the subtracting unit. 2. Device by π. 1, characterized in that each detector contains the first and second elements And, the combined first inputs of which are the signal input of the detector, and the second inputs of the elements And connected to the corresponding inputs of the gate of the detector, the output of each of the elements And through the corresponding memory block is connected to the input of the adder The output of which is connected to the input of the integrator, the output of which is the output of the detector, the combined synchronization inputs of the memory blocks are connected with a sync detector input. 3. The device according to claim. 2, so that each . The memory block of the detectors contains a short-circuit flip-flop, the signal input of which is the input of the memory block, and the output is connected to the signal input of the D-flip-flop, the sync input of which is connected to the reset input of the K3 trigger and is the sync input of the memory block.