SU1292194A2 - Device for checking conditions of communication channels from signal-to-noise ratio - Google Patents

Abstract

The invention relates to telecommunications. With respect to A.N. 613508, the accuracy of the control is improved by compensating for the influence of the shape of the interference spectrum. The device contains a nonlinear converter 1 of the input signal, a narrowband filter 2, an expander - a coherent signal converter 3, a rectifier 4 of the input signal, a subtraction unit 5, a voltage divider 6, a nonlinear converter of a coherent signal. Newly introduced narrowband filter 8, rectifier 9 interference, block 10 subtraction 1 Il. / fe / XO e with N3 CO "4;

Description

MS)

The invention relates to telecommunications and can be used to monitor the state of communication channels in terms of signal-to-interference ratio in the transmission of discrete information and is an improvement of the invention according to the author. No. 613508.

The purpose of the invention is to increase the control accuracy by compensating for the influence of the shape of the interference spectrum.

 The drawing shows a structural electrical circuit of the proposed device.

A device for monitoring the state of communication channels with respect to the signal-to-noise ratio contains a non-linear converter 1 of the input signal, a first narrowband filter 2, a rectifier

3 coherent signal rectifier

4 input signal, first subtractor 5, voltage divider 6, nonlinear coherent signal converter 7, second narrowband filter 8, interference rectifier 9, second subtraction unit 10.

The device works as follows.

The nonlinear converter 1 removes the phase shift of the input signal. The characteristic of such a converter has, for example.

was going

ex,

ri ug. de Ugx,

to, and

m

1 8x, -, Kg

 II -

and

- j mni

8x

  - gbixi voltage, respectively, at the input and output of the nonlinear converter 1; -, complex amplitude; S2 - carrier frequency

input signal; m i 2, with m being an even number;

K - coefficient of proportionality p-multiplicity of phase manipulation.

-

Signals from the output of block 10 and from the output of rectifier 4 of the input signal are fed to the inputs of block 5, at the output of which voltage is obtained that is proportional to the level of interference in the communication channel. This voltage is applied to one of the inputs of the divider 6, for example, the second input of which is supplied with voltage from the output of block 10

The narrowband filter 2 from the output voltage of the nonlinear converter 1 extracts the voltage at a frequency. In this voltage, there are 55 subtractions. As a result, there are no signal components at the output, and voltage modifier 6 is obtained by foot-harmonic interference if the latter is present in the communication channel. Voltage output from narrowband filter 2

a signal proportional to the signal-to-noise ratio in the communication channel, which can be applied to the recording

921942

is converted to a voltage of, for example, a direct current by the rectifier 3 of a coherent signal. The characteristic of nonlinear converter 7 is 5

Alas where and 6,

 To / and

t

vi-g

Zyk

ten

G5

20

;

.

35

voltage respectively

the input and output of the nonlinear converter 7; K - coefficient of proportionality.

. The voltage and, proportional to the sum of the amplitudes of the useful signal and monoharmonic, close to the frequency of interference.

The voltage at the output of the narrowband filter 8 is a monoharmonic interference, purified from the signal and other interference. Phase-manipulated signal; 1n and other modulated interference have a spectrum that is much wider than the passband of the narrowband filter 8 and therefore is absent at its output. As a result of the monoharmonic JQ transform, the rectifier 9 generates a DC voltage, which in block 10 is subtracted from the output voltage of the non-linear converter 7 of the coherent signal. Thus, at the output of the subtraction unit 10, a voltage is generated that is proportional to the amplitude of the useful signal and is independent of monoharmonic interference. Block 10 of subtraction Q is identical to block 5 of subtraction and can be performed, for example, in the form of a DC amplifier with negative feedback and a differential input.

The signals from the output of subtraction unit 10 and from the output of rectifier 4 of the input signal are fed to the inputs of subtraction unit 5, the output of which is a voltage proportional to the level of interference in the communication channel. This voltage goes to one of the inputs of the voltage divider 6, the second input of which receives the voltage from the output of the block 10

45

50

- 55 subtraction. As a result, the output of the divider 6 voltage is obtained

subtraction. As a result, the output of the divider 6 voltage is obtained

a signal proportional to the signal-to-noise ratio in the communication channel that can be fed to the recording

312921944

a device or a threshold device connected second narrowly (not shown). A filter with input connected to a nonlinear input input formula, an input signal and a voltage equalizer, output of a nonlinear transducer to monitor the state of the coherent signal generator of the communication channels with respect to the signal / connected to the second inputs of the first disturbance by auth.St. No. 613508, about the tl of the subtraction and divider unit, in order, through the introduced second unit, to increase the accuracy of control due to W reading, the second input of which compensates for the influence of the shape of the spectra on the output - interference, it introduced a sequence of mechs.

Claims (1)

Claim A device for monitoring the state of communication channels in relation to signal / noise ratio according to ed. No. 613508, characterized in that, in order to improve the accuracy of the control by compensating for the influence of the shape of the interference spectrum, a second narrow-band filter is sequentially connected to it, the input of which is connected to the input of the nonlinear converter of the input signal, and a rectifier 5 noise, the output of the nonlinear converter of coherent the signal is connected to the second inputs of the first subtraction unit and voltage divider through the introduced second reading unit 10, the second input of which is connected to the output of the interference rectifier.