SU253115A1 - DEVICE OF RECEPTION OF BIPULAR SIGNALS - Google Patents

Description

The invention relates to the field of telecommunications, specifically to the field of receiving binary signals via optical and cable communication lines.

As it is known, the most noise-resistant system for transmitting multi-channel messages over cable and optical communication lines is the Pulse Code Modulation (PCM) system. In such a system, a multi-channel message is transmitted in pulses in binary form, with the binary code being transmitted in various ways.

At the receiving point, the recognition of "1 and" O information is carried out by gating the received signal-to-sound mixture in the middle of the expected pulse. Depending on the received voltage value, a decision is made to receive one or another binary information symbol.

However, potential noise immunity is not achieved in existing PCM reception schemes. This is due to the fact that all processing of the signal-to-noise mixture consists only in correcting the frequency response of the transmission path. The circuit of such a receiver consists of an amplifier, a gating circuit and a strobe pulse generator. In this case, the noise immunity of information transfer is determined by the ratio of the instantaneous value of the signal voltage to

the instantaneous value of the voltage of the schum at the time of the appearance of gating pulses and therefore well below the potential noise immunity.

In order to obtain maximum signal-to-noise ratio at the time of gating and, consequently, maximum noise immunity of PCM transmission systems using bi-pulse form of video signals, it is proposed to enter into the receiver between the amplifier and the gating circuit a cumulative circuit consisting of two consecutively connected subtractors, and in parallel each of them includes delay lines and an integrator without a reset.

Thus, in the proposed receiver circuit, a preliminary processing of the signal-to-noise mixture is introduced. Immunity is determined by the ratio of the total signal energy

for the period of transmitting the information symbol to the weakly correlated noise energy.

This is achieved by the fact that the received signal-to-noise mixture enters the subtractive device and simultaneously on the delay line (with a delay time equal to half the time of transmitting one symbol of binary information). The signal that passes the delay line is subtracted from the signal present in the subtracting device. Then, the delay line and the subtractor, from the output of which the transference reaches the integrator without a reset, the integration time must be much longer than the duration of one information symbol.

FIG. 1 shows a block diagram of the device; in fig. 2 shows time diagrams of voltage at various points in the circuit.

The device contains an amplifier 1, designed to amplify the input signal. To the desired value; a first subtracter 2 and a first delay line 3 serving to increase the signal-to-noise ratio; a second subtractive device 4 and a second delay line 5, by which the signal-to-noise ratio is further increased; an integrator 6, which makes it possible to estimate the converted signal-to-noise mixture by energy; gating circuit 7 providing regeneration of the transmitted binary message; a strobe pulse generator 8, which forms a short clock pulse from the received signal at times of maximum signal-to-noise ratio.

The receiver works as follows.

The amplified signal (Fig. 2, a), the connecting link, is fed to the subtractor 2 and the delay line 3. The voltage generated at the output of the delay line (Fig. 2.6) is subtracted from the voltage of the signal and in the subtractor and the voltage obtained (Fig. 2, i) is fed to the input of the second delay line 5 and the second subtractive device 4, due to which a voltage is formed (Fig. 2, e}, which is fed to the input of the integrator 6.

From the output of the integrator, the voltage (Fig. 2, e) is fed to the gating circuit 7, which is also supplied with short pulses (Fig. 2, g) from the strobe pulse generator 8. The gating scheme makes a decision on the "1 or" transfer of the transmitted information.

Thanks to the first subtraction scheme and the delay line, the amplification of the CI-nal is obtained. Since, with a delay of half the period allotted for transmitting one binary information symbol, the noise autocorrelation coefficient is significantly less than one, an increase in the signal-1 sub ratio is obtained at the output of this circuit. With secondary delay and subtraction, this ratio increases further.

At the output of the second subtractive device, the pulses are twice as different in duration as in the amplitude (depending on the following "1 and" About information),

Irice.m short pulses have a large amplitude, and long pulses - a smaller one. As a result, the peak values of the voltage at the integrator output at times, separated by clock intervals, are the same and are proportional to the total signal energy. At these times, gating is performed, and the decision to accept a "1 or" about information is made by the polarity of the voltage at the time of gating.

The gain in respect of sial noise from the use of the proposed processing circuit 11p 1p of that signal, as compared with the known schemes, is eight times in power, which will significantly increase

the range of the communication lines, or eight times to reduce the transmitter power.

NOTICE of invention

A biopulse signal receiving device comprising its amplifier, a gating unit and a strobe pulse generator, characterized in that, in order to increase the noise immunity of the pulse code modulation systems, between the amplifier and the gating unit, the drive is turned on, and the drive is made, for example, connected two subtractors with delay lines on each of them, and an integrator without resetting,

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