SU1700756A1 - Method and device for checking communication channel - Google Patents

Abstract

The invention relates to telecommunications. The purpose of the invention is to improve the accuracy of determining the frequency range of the monitored parameter. The proposed method and device ensure that all measurements are carried out in the same cat ordinate system, and therefore there is no need to determine the relative deviations of the parameter, and the thresholds are corrected by the deviation of the monitored parameter from its nominal value. The device contains a matching unit 1, analog-to-digital converter 2, averaging unit 3, adder 4, parameter amplitude analyzer 5 indicator 6, parameter changing speed analyzer 7, threshold unit 8, jump duration counter 9, blocking driver 10, divider 11, accumulating adder 12 register 13 of the nominal value of the parameter and block 14 of the comparison. 2 sp.f-ly, 1 ill. with s

Description

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The invention relates to telecommunications and can be used in static monitoring of jitter and phase jumps or fluctuations in the level of amplitude jumps in a communication channel.

The purpose of the invention is to improve the accuracy of determining the frequency range of measurement of a controlled pair.

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The drawing shows a structural circuit of the device that implements the proposed method.

The device for monitoring the communication channel comprises a matching unit 1, an analog-to-digital converter (ADC) 2, averaging unit 3, a parameter 4, a parameter oscillation magnitude 5, an indicator 6, a parameter changing analyzer 7, a threshold unit 8; a jump time counter 9, a lock driver 10, a divider 11 accumulating the adder 12, a register 13 of the nominal value of the parameter and a comparison block 14.

The essence of the proposed method is that all measurements are carried out in the same coordinate system, g connection with which it is not necessary to determine the relative parameter deviations, and the set thresholds are corrected by the deviation of the monitored parameter from its nominal value.

The device for monitoring the communication channel operates as follows.

From the output of the monitored communication channel, the measuring signal is fed to the input of the matching unit 1, which coordinates the measuring path with the monitored channel, as well as low-frequency filtering of the c signal to form a back-cut of the frequency response.

From the output of block 1, the signal is fed to the A / D converter 2, which converts the measured parameter to a digital code.

The adder 4 compares the digital code received from the output of the ADC 2 with the expectation signal arriving at the second input of the adder 4.

The difference signal at the output of the adder 4 is the instantaneous value of the magnitude of the switch off of the measured parameter and is fed to the input of the analyzer of the torus 5 of the oscillation amplitude of the parameter, which stores the maximum (positive and negative) deviations

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Neither of the parameters and sums them, forming the oscillation range of the parameter, which is indicated by the indicator 6. This parameter characteristic at amplitude measurements determines the magnitude of the level fluctuations, and at phase measurements the phase jitter value.

The instantaneous deviation of the measured parameter is generated by the adder 4 after each cycle of operation of the A / D converter. At the same time, after recording the received information in the adder 4, the information is copied to the controlled divider 11, where the division cycle is started. After the end of the division, the magnitude of the instantaneous value of the measured parameter reduced by M times is fed to the input of accumulating adder 12, where it is summed with the previous value of the mathematical expectation, thereby forming its new value. Thus, the formation (correction) of the mathematical expectation is carried out at each reading of the A / D converter 2.

Setting the lower limit of the frequency range of the change in the measured parameter is performed by selecting the value of the division factor M of the controlled divider 11 determined as a result of rounding to the value of the nearest binary bit:

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quantization frequency of the measured parameter, i.e. the sampling frequency of the ADC 2; the specified frequency of the lower limit of change of the measured parameter;

N is the proportionality coefficient, taking into account rounding to the nearest binary bit.

At the frequency of the input signal (sampling frequency of the ADC 2) 1020 Hz and the lower one, the range is 4 Hz, the coefficient and at Frp.n 20 Hz

The installation of the coefficient M in the proposed device is carried out before the start of measurements using the switches of the divider 11.

The change of the frequency range towards the lower frequencies is carried out by selecting the division factor M.

The instantaneous values of the parameter A (t), generated at the first output of the A / D converter 2, are received at averaging unit 3, where they are summed up within two seconds, since the average value of the parameter is obtained by summing up the counts of the instantaneous values of the parameter.

In block 3, the averaging is shifted to the right by n bits of the summation result, which is equivalent to dividing by 2H, i.e. averaging unit 3 performs an operation in accordance with the known expression 2P

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where A is the average value

parameter; n is an integer specifying

averaging accuracy; K is the number of samples of instantaneous parameter values used to determine the average.

Comparison unit 14 sums the signal obtained from averaging unit 3 with a preset in the register 13 with an additional code of the nominal parameter value and forms the value of the mean deviation of the parameter from its nominal value, which is indicated by indicator 6.

When measuring the amplitude characteristics of the communication channel, this parameter corresponds to the magnitude of the residual attenuation, and when measuring the phase characteristics, to the frequency deviation.

The obtained signal of the average deviation of the parameter enters the block of 8 thresholds, where, by summing up with the preliminary (before

nor) by the threshold value of the parameter jump included in it, corrects the latter by the value of the average deviation of the measured parameter. In addition to the corrective adder, the threshold block 8 contains a comparison circuit that compares the instantaneous deviation of the measured parameter from the adder 4 with the correc

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jump threshold. The signal of exceeding the threshold from the block of 8 thresholds enters the counter 9 of the jump duration, which analyzes it for compliance with the criterion of the jump of the parameter in terms of duration.

The signal generated at the output of the counter 9 for the duration of the jump, provided that the specified criterion is met, is fed to the indicator 6. The same signal turns on the blocking generator 10, which blocks the passage of the measuring signal in the analyzer 7 for changing the parameter for a certain time.

The latter, by appropriate processing of the instantaneous values of the deviations of the measured parameter coming from the adder 4, determines the value of the parameter increment over a specified time and gives (if the conditions necessary for fixing the parameter jump on the rate of change) are satisfied, the enabling signal for subsequent analysis is in block 8 thresholds .

Claims (2)

Invention Formula one-. The control method of the communication channel, including the formation of the mathematical expectation of the value of the monitored parameter, the determination of the maximum swing of the parameter value by the sum of its maximum positive and negative deviations, the establishment of threshold values for the monitored parameter jump, the determination of the rate of change of the monitored parameter, the comparison of the deviation of the monitored parameter with the previously adjusted its threshold values and determining the duration exceeded and the threshold, characterized in that, in order to increase the accuracy of determining the frequency range of the monitored parameter, the expectation of the monitored parameter value is formed at each counting instantaneous value of the received signal by summing the expected value of the monitored parameter with the M deviation of the next monitored parameter value the expected value, and the correction of the threshold values of the monitored parameter is carried out according to the mean deviation o of nominal value, and M is determined by the formula M N f Kfi F Vp.H ) where fRg is the quantization frequency of the received signal when determining the value of the monitored parameter; Fr - set lower bound frequency range of the monitored parameter; N is the proportionality coefficient, taking into account the rounding of the result to the value of the nearest number, equal to the power of 2. 2. A device for monitoring a communication channel, comprising a series-connected matching unit, an analog-to-digital converter and an averaging unit, a series-connected adder, a parameter oscillation magnitude analyzer and an indicator, five 0 serially connected parameter rate analyzer, threshold block, jump duration counter and blocking driver, the first and second inputs and output of which are connected respectively to the second indicator input, the second output of the analog-digital converter and the first parameter analyzer speed input, TL it is connected with the fact that serially connected divisor and accumulating adder and serially connected register of nominal parameter value and comparison unit are entered, while the output of the averaging unit is connected to the second input of the comparison unit, the output of which is connected to the third input of the indicator and the second input of the threshold unit, the third input connected to the second input of the parameter rate analyzer, to the input of the splitter and the output of the adder, the first and second inputs of which are connected respectively with the output of the accumulating adder and with the output of the analog-digital converter.