SU1376249A1 - Apparatus for measuring degree of protection of signal from noise - Google Patents

Abstract

The invention can be used to automate the evaluation of the quality of complex signals. The purpose of the invention is to increase the accuracy of measuring the signal immunity from interference. The device contains a receiver 1, a divider 2 frequencies, a key 10, a driver (F) 11 gating pulses, consisting of r-12 pulses, dif. chains 13, p keys 15 and source 16 of reference voltages, signal converter 17, consisting of p parators 18, p-1 delay electrodes 19 and n input el-block OR 20, adder 21. F 3 reference noise was introduced, Ф 4 signals, two multipliers 5, two integrators 6, two quadrants 7, an adder 8, a normalizing unit 9. In Ф 11 a differential is entered. chain 14. 1 Il. I w

Description

The invention relates to telecommunications and can be used to automate the assessment of the quality of complex signals.

The purpose of the invention is to improve the accuracy of measuring the signal immunity from interference.

The drawing shows a structural electrical circuit of the device for measuring the security of a signal against interference.

The device contains a receiver 1, a divider 2 frequency, shaper 3 reference interference, shaper 4 signal, two multipliers 5, two integrators b, two quadrators 7, adder 8, normalizing unit 9, key 10, shaper 11 gating pulses, consisting of generator 12 pulses, the first 13 and second 14 differentiating chains, n keys 15 and the source 16 of the reference voltage signal converter 17, consisting of n comparators 18, n-1 delay elements 19 and n input element OR 20, adder 21 and counter 22,

The device works as follows.

On the transmitting side, the signal under investigation is formed, which is fed to receiver 1. As a measure of the effectiveness of signals under the influence of interference, the coefficient of the mutual difference of signals and interference is taken. The signal from the output of the receiver 1 is fed to the first inputs of the multipliers 5. The second input of the first multiplier 5 is supplied with a reference interference from the first output of the imaging unit 3 of the reference noise, and the second input of the second multiplier 5 is supplied with the signal of the imaging device 4 of the signal coupled to Gil

Bertha with reference noise. The signals obtained as a result of multiplication from the outputs of multipliers 5 are fed to the first inputs of integrators 6, where the integration process takes place over a time interval equal to the duration of the element of the signal under investigation t € 0. From the outputs of the integrators 6 signals are sent to the quadrants 7, and then to the inputs of the adder

The pulse generator 12 generates rectangular pulses with a duration equal to the duration of the element, with the signal T being studied, and their tracking period T, which arrive at the inputs of the differentiating circuits 13 and 14. The first differentiating circuit 13 is designed to form gating pulses on the leading edge of the rectangular pulses , coming from the output of the generator 12 ,,., and the second differentiating circuit 14 - for the formation of gating pulses along the trailing edge of the rectangular pulses. The gating pulses from the output of the first differentiating circuit 13 are fed to the input of the generator 3 of the reference noise and to the second inputs of the integrators 6 to control the start of operation of these blocks. The gating pulses from the output of the second differentiating circuit 14 are fed to the third inputs of the integrators 6 (as

50

8. From the output of the adder 8, the signal of the post of reset pulses) and on controls to the first input of the normalizing unit 9, the second input of which is connected to the third output of the driver 3 of the reference noise. With normalizing

key input 10 for counting the measurement result. The ratio of the duration of the rectangular pulses T and the period they follow is selected

unit 9, the signal is fed to the information input of the key 10, in which, at its control input of the strobe pulse, the measurement result of the coefficient of mutual difference between the signal and the reference noise, described by the following expression, is read out;

B-25: r Bb V

l-ljz, (t) z ,, (t)

where Z (t) Zng (t) is a function of time,

determining the structure of the investigated signal and the reference noise;

our.

Zn, (t) - function of time, Hilbert conjugate with

Uh

kl

P-

(t) dt

Zn, (t);

- reference interference power;

- the duration of the element of the signal under study.

The pulse generator 12 generates rectangular pulses with a duration equal to the duration of the element of the signal T under study and the period of their following T which arrive at the inputs of the differentiating circuits 13 and 14. The first differentiating circuit 13 is designed to form gating pulses along the leading edge of the rectangular pulses along - the generator 12, stepping from the output of the generator, and the second differentiating circuit 14 - for the formation of gating pulses along the trailing edge of the rectangular pulses. The gating pulses from the output of the first differentiating circuit 13 are fed to the input of the generator 3 of the reference noise and to the second inputs of the integrators 6 to control the start of operation of these blocks. The gating pulses from the output of the second differentiating circuit 14 are fed to the third inputs of the integrators 6 (as

key input 10 for counting the measurement result. The ratio of the duration of the rectangular pulses T and the period they follow is selected

of the condition & 2 T; about . In this case, the time error of the error of the elements of the signal under study and the reference error changes. If the signal and the reference noise have the same structure, then in some measurements there are possible cases of their synchronization, which corresponds to creeping the maximum value of the mutual difference coefficient (similar to the process of convolving a complex signal in the correlation device). Each readout of the measurement result, after leaving the output of the key 10, results in the output of the comparators 18-18 of the converter of the 17 pulses, while the pulses are formed at the outputs of those comparators, the threshold voltages at the second inputs of which do not exceed the value of the reference. The threshold voltages are supplied from a source of ..16 reference voltages via keys 15-5 that are controlled by gating pulses from the output of the second differentiating circuit 14.

Impulses from the outputs of the comparators 18, - 18f | arrive through elements 9 - 19у, -1 of the delay to the corresponding inputs of the p - input element OR 20. The delay elements of the converter 17 provide the time separation of pulses.

Thus, after each i-ro measurement, depending on the magnitude of the coefficient of mutual difference g; the output of the Converter 17 received the corresponding number of pulses. Then a sequence of pulses is fed to the input of a pulse adder 21 intended to sum the N measured values of the mutual difference coefficient and obtain the value of g,

I - I

from the output of the adder 21, information about the result obtained goes to the first input of the divider 2.

Upon receipt of the N-ro gating pulse (where N is some predetermined number of measurements of the coefficient of mutual difference between the signal under study and the reference noise) at the input of counter 22, which is connected to the output of the second differentiating circuit 14, 12 pulses signal to stop the gene

Q 5 0 5

ABOUT

5 0 5

0

rator, and from the first output of the counter 22 to the second input of the divider 2, information is received on the number of measurements made N. The divider 2 makes the final calculation of the average statistical estimate of the coefficient of mutual difference in the form 1 N

l 1 g-

8 m Z.- §1

iN; ,

information about which is fed to the output device for display.

Claims (1)

Invention Formula A device for measuring the immunity of a signal from interference, containing a receiver, a key, a signal converter consisting of a n-input element S1J, each of np-1 inputs of which are connected through a corresponding delay element to an output corresponding to n-1 comparators, and n - an input connected c, the output of the nth comparator itself, the output of the key is connected to the first inputs of each of the n comparators, the gate driver that consists of a source of reference voltages, n keys, the first input of each of which is connected to The output of the reference voltage source, serially connected pulse generator and the first differentiating chain, the output of each of the gating pulse shaping keys is connected to the second input of the corresponding comparator of the signal converter, in order to increase the accuracy of signal protection from interference, A counter, a frequency divider, an adder, a serially connected reference driver, the first multiplier, the first integrator and the first square are entered. op, serially connected signal conditioner, second multiplier, second integrator and second quadrant, second inputs of each multiplier are connected to receiver output, second output of reference noise generator is connected to input of signal generator, second input of first integrator is connected to second input of second integrator, with input form of the reference noise generator and with the release of the first the differentiation of the chain of the gating pulse former, the sum is JTOpa, the first and second inputs of the gateway are connected to the output of the first and second quadrants, respectively, nor-. the first unit whose input is connected to the output of the adder, the second input to the third output of the reference driver, and the output connected to the information key input, the second differential circuit, the input of which is connected to the output of the pulse generator, is entered into the gate generator, and the output 15 connected to the control key input, chen to the input of the pulse generator. 0 five to the third input of each of the integrators and to the second inputs of each of the keys of the gating pulse generator, the first input of the counter is connected to the generator output, and the second input to the output of the second differential circuit of the taper generator, the first input of the frequency splitter is connected to the output of the counter, the output of the adder is connected to the second input of the frequency divider, and the input is connected to the output of p - the input element OR of the signal converter, the second output of the counter is connected