SU1169182A1 - Device for automatic checking of gain factor of sound channel - Google Patents

Description

The invention relates to electrical engineering and can be used for

control of the transmission coefficient in the channels and the sound transmission of sound and television broadcasting. five

The purpose of the invention is to improve accuracy.

FIG. 1 shows the block diagram of the proposed device; in fig. 2 - an embodiment of the converter, analog code; Fig, 3 is an embodiment of the block tolerance signal processing.

The device for automatic control of the sound transmission coefficient of the sound channel contains the first 1.1 and second 1.2 input amplifiers, the first 2.1 and the second 2.2 detectors, the first 3.1 and the second 3.2 integrators, the analog-code converter 4, 20'5 tolerance signal processing unit, the threshold unit 6, the matching element 7, the decoder 8, the display unit 9. .

The analog-code converter contains 25 operational amplifier 10, comparator 11, digital-to-analog converter 12, counter 13, oscillator 14 clock pulses, and element 15.

The signal processing unit 30 contains the shaper 16 of the tolerance code, the element 17 and the comparator 18.

The device works as follows.

The signals from the input and output of the controlled sound channel are fed to the inputs of the first 1.1 and second 1.2 input amplifiers, respectively.

From the output of the first 1.1 and second 1.2 input amplifiers, the signals are fed, respectively, to the inputs of the first

2.1 and 2.2 second detectors, the percentile voltage from which is fed to the inputs of the first 3.1 and second 3.2 integrators respectively. To eliminate the influence on the measurement accuracy of the phase shift transmission coefficient in the controlled path, the integration time should be of the order of 100 ms. 50

From the release of the first 3.1 and second

3.2 integrators signals are received respectively at the first and second inputs of the converter 4 analog-code, where the ratio of these two signals 55 is converted into a digital code.

From the output of the converter 4 analog-code information is fed to the input

block 5 of the pre-processing signal, where the digital code characterizing the transmission coefficient of the sound channel is compared with the codes that characterize the specified tolerance for the transmission coefficient.

The matching results, which are the results of the automatically conducted tolerance control of the transmission coefficient of the sound channel, are sent to the decoder 8, where they are converted into information that then goes to the display unit 9, in which the corresponding deviation of the transmission coefficient of the sound channel from the tolerance is displayed.

At the same time, information characterizing the transmission coefficient of the sound channel from the additional output of the converter 4 analogue code is sent directly to the input of the decoder 8, where it is converted into information that then enters the digital indicators of the block 9. Thus, the transmission coefficient is measured, for example, percent.

Considering that the real sound signal of the sound varies within large limits (dynamic range of about 40 dB) and that at small signal levels the conversion results in analog-code converter 4 (due to the discreteness of the process) may differ from the true signal values, comparing the monitored signals to small ones levels not effective. Therefore, when the signal decreases below the threshold, at which the specified accuracy of monitoring the sound channel transmission coefficient is no longer realized, a voltage is generated at the output of threshold block 6 (representing a limiter with a predetermined trigger threshold), which is fed through matching element 7 to an additional input of block 5 and to exclude from measurements (indication) of signals whose value is below a predetermined threshold.

Analog signals from the outputs of the first 3.1 and. the second 3.2 integrators (Fig. 1) are fed, respectively, to one of the inputs of the comparator 11 and the input voltage reference of the digital-to-analog converter (DAC) 12.

To the second input of the comparator · 11

3

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(Fig. 2) comes through an operational amplifier 10 analog signal from the output of the DAC 12. The counting input of the counter 13 through the element 15 receives the clock pulses from the generator output 14 clock pulses. The counter 13 is connected by its outputs to digital inputs of a DAC 12. In comparator 11, a converted analog signal is compared with an analog signal from a DAC 12. If the analog signal coming from the DAC 12 is less than the analog signal being converted, the comparator 11 generates the level "1", otherwise - the level "O", which, acting on the element And 15, closes it and stops the supply of clock pulses from the generator output 14 and the counting input of the counter 13.

With the equality of the analog voltage at the output of the DAC 12s convertible analog voltage supplied to the second input of the comparator 11, the following relationship takes place:

^and s = u, = and _2. | _p K a · 2 "'(1)

and from here

G £ a-2 ^{<, =} 31 2 "17?) V,

one

transmission coefficient of the measured path; (2)

digital equivalent of the transfer coefficient 35 measured path; the weight of the discharge digit of the digital code with the magnitude of the voltage quantum equal to

"2" *

the number of digits $ digital code; the number of pulses arriving at the input of the counter 13 ',

V, - analogue ^ν 2 breakable voltage supplied to the second input of the comparator 11 ·, - analogue ν ₃ tensile voltage coming to the input voltage reference DAC 12; - analog voltage graduation output output operational amplifier 10. full cycle of work

at the outputs of the counter 13 (the outputs of the counter according to the information are the same), a digital code is generated corresponding to the measurement results of the transmission coefficient of the sound path being monitored. This code is received, respectively, at the second input of the comparator 18 of block 5 (FIG. 3) and the input of the decoder 8 (FIG. 1).

A digital code characterizing the transmission coefficient of the sound channel being monitored, from the output of the converter 4, the analog-code (Fig. 1) is fed to the second input of the comparator 18 of block 5, to the first input of which the output of the shaper 16 of the tolerance code is a digital code characterizing the specified tolerances transmission coefficient. In the comparator 18 compares the current values of the transmission coefficient with the specified tolerances. The results of the comparison, which are the results of the automatically conducted tolerance control of the transmission coefficient of the sound channel, are received from the output of the comparator 18 through the element 17 and the input of the decoder 8 (Fig. 1), while the second input of the element 17 is fed with the information from the output of the matching element 7, which is used to exclude unreliable values from measurements.

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Claims (3)

1. DEVICE FOR AUTOMATIC CONTROL OF THE SOUND CHANNEL TRANSFER COEFFICIENT, containing the display unit, connected in series the first input amplifier, whose input is the input of the sound channel being monitored, the first detector and the first integrator, the threshold unit and the second input amplifier connected in series, the input of which is the output of the monitored channel sound, the second detector and the second integrator, characterized in that, in order to improve accuracy, a matching element was introduced into it and connected in series The analog converter, the signal processing unit and the decoder, the output of which is connected to the input of the display unit, the outputs of the first and second integrators are connected to the first and second inputs of the converter analog-code, the second output of which is connected to the second input of the decoder, output the first integrator is connected to the input of the threshold unit, the output of which is connected via a matching element to the control input of the tolerance signal processing unit. 2. The device according to claim 1, which is based on the fact that the analog-code converter is made in the form of a series-connected clock generator, an And element, a counter and a digital-to-analog converter, connected in series with an operational amplifier and a comparator, the output of which is connected to the second input Element And, the first and second inputs and output of the operational amplifier are connected respectively with the first and second outputs and the second input of the D / A converter, the third input of which and the second input of the comparator are respectively the first and second inputs of the analog converter — the code, whose first and second outputs are the first and second outputs of the counter, respectively. 3. The device according to p. 1, characterized in that the block tolerance signal processing is made in the form of serially connected shaper code of the tolerance, digital comparator and the element And, the output of which is the output of the unit tolerance signal processing, input and whose control input is, respectively, the second input of the digital comparator and the second input of the element I. 1169182- one 1169182 2