SU364113A1 - DEVICE CONTROL RELATIONS SIGNAL / NOISE - Google Patents

Description

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This invention relates to the field of communications.

Devices are known that allow measurement of the signal-to-noise ratio in communication channels when transmitting information through it.

The prior art devices do not control the signal-to-noise ratio in the frequency band that is not related to the width of the signal spectrum.

Also known are devices for controlling the signal-to-noise ratio, for which a separate noise source is required, with a power varying in proportion to the noise power in the signal channel.

The purpose of the invention is to improve the accuracy of control and exclude an auxiliary source of schum.

This is achieved by the fact that the output of the analog-code converter is connected to the counter module of the sum and, through a counter module of the difference, to the digital and integrated grid for vertical and lower thresholds. The output of the sum module module is connected to the second inputs of the integrators through the appropriate dividers.

The drawing shows a diagram of the device.

The device contains a broadband amplifier /, kinematic filter 2, analog-to-code converter 3, modulus difference counter 4, sum module mod. We 5, divider 6 with division factor Ki, divider 7 with division factor Kg, digital integrator 8 for a lower threshold, digital integrator 9 for the upper threshold and chroniser 10.

The device filters the signal and noise in the pulse spectrum band, separates the signal and noise, separates the signal level and noise modules separately and compares the obtained ratio of the signal module to the module module with a predetermined threshold. In this case, the threshold does not depend on the signal level or the noise, but is determined by the permissible signal-to-noise ratio for the given conditions of transmission of information in the communication channel.

The kinematic filter 2 is an integrator that is zeroed when control arrives at its input signals from the chroniser 10.

The analog-code converter 3 memorizes the level of the bipolar signal arriving at its input and outputs the sign and the magnitude of the amplitude of the signal at the input.

The module of the difference module 4 is an adder that outputs the module of the algebraic difference of two numeric codes, which enter 5 at its input for one character.

The modulo-sum counter 5 is the adder of the algebraic sum of two codes for the duration of one character. Dividers 6 and 7 are counters operating in long-frequency mode.

The division ratio is set manually before operation.

Integrators 5 and 9 are digital integrators with a limiter on the output function, which retain the specified level when filled before the input of signals of a reverse sign.

Chronizator 10 is a generator with dividers generating control and synchronization signals. The divisor of the chroniser 10 is synchronized by a synchronization signal — a meander, the period of which is equal to the duration of the symbol.

A bipolar telegraph signal with noise is fed through the input // and the amplifier / to the input of the kinematic filter 2. During the first half of the symbol duration, the signal is integrated with the noise in the kinematic filter 2. In the middle of the symbol, the signal level with schulum accumulated in the filter is fed to the input of the analog-code converter 3 and stored in it, and the kinematic filter is zeroed by the signal of the chroniser. Then, in the kinematic filter, the second half of the symbol is integrated, and in converter a 1alog-, frame 3, the sign of the voltage applied to its input is determined from filter 2, the amplitude of which is encoded with a binary code. According to the clock signals B, the received signals of the binary code and the sign come from the converter to the inputs of the counters of the difference module 4 and the sum 5 module in which the first number is stored. At the end of the symbol but the signal of the synchronizer 10, the kinematic filter 2 is zeroed out, and the level of the signal with noise at its output is not zeroed and the analog-code is stored in the converter. In the kiematic filter 2, the first half of the next symbol is integrated, and in the converter 3, the sign of the amplitude value of the memorized level is determined. Then from the output of the converter 3, the counters of the difference module 4 and the sum of 5 receive the second number and its sign.

In counter 4, the algebraic difference of two numbers is determined, and the code of the modulus of difference from the counter comes in the input of the subtraction of the integrator 9.

At the same time, in counter 5, the value of the algebraic sum of two numbers is determined, and the sum module code, delayed relative to the difference modulus code due to control signals, goes to dividers 6 and 7. From the output of divider 6, the number of the sum module code decreases by input addition of integrator 9, and from the output of divider 7 reduced by K2 times the number of the code of the module of the sum goes to the input of the subtraction of integrator 5.

The difference modulus 4 and sum 5 counters are zeroed.

These operations are repeated for the second and subsequent characters. 5 In integrator 9, the difference is accumulated between the code of the module su.mma, reduced by Ki pa: i, and the code of the module difference. If the sign of the accumulated difference is positive, the output 12 from the integrator 9 is signaled that the upper threshold of the signal.L / m ratio is exceeded, and if the sign is negative, the signal on excess of the norm is not output.

At the same time, in the integrator 8, a difference is accumulated between the difference modulus and 5 moduli reduced by a factor of K2. If the difference sign is negative, nothing is output to the integrator, and if the difference sign is positive, output 13 from the integrator receives a signal that the lower threshold of the signal-to-noise ratio is not exceeded.

During operation, the chronizer 10 through the input 14 enters the meander 2, the synchronizing divider of the chrysantorizer. The signals of the chronizer, which control the filter m. 2, coincide with both fronts of the meander, and the signals of zeroing of the counters 4 and 5 coincide with the front of the meander, which does not coincide with the beginning (symbol) of the symbol.

When the transmission rate of the monitored signal changes, the period of the synchronization signal changes, the division factor in the chronizator changes, integrators, dividers and module counters reset, and the signal-to-noise ratio control process resumes.

With a significant difference in the transmission speed of the monitored signal, the gain of the amplifier / is switched, which has an automatic gain control.

Subject invention

A signal-to-sound ratio control device containing a broadband amplifier, connected via an kinematic filter to an analog converter (code and digital integrators for upper and lower

Thresholds, the outputs of which are the output of the device, characterized in that, in order to increase the accuracy of control and eliminate the auxiliary noise source, the analog-code output of the converter is connected to the counter of the sum module and, through a difference module counter, to digital integrators, to the second inputs which through the appropriate dividers connected to the output of the counter module amount.

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