SU1626433A1 - Duplex data transmission system - Google Patents

Abstract

The invention relates to interconnection. The purpose of the invention is to reduce the level of crosstalk with duplex information over a two-wire communication line. The system consists of two transceiver stations, and 2, connected by a two-wire communication line 3. Each station 1 and 2 consists of a receiving 5 and a transmitting 4 amplifiers. The receiving terminal is made on pairs of optocouplers 9 and 10 with LEDs. The selection of the received signal is based on the compensation effect: the transmitted signal is subtracted from the signal mixture received by the optocouplers 9 and 10. The non-linear distortions of the received signals are compensated by the principle of assigning a floating operating point to the LEDs. For this purpose, a synchronizer 19 serves as an additive to the transmitted signal, with the amplitude of the additive being equal to the width of the chrominance of the LED, and polarity of the polarity of the current in the receiving terminal circuit. The current strength is determined by comparators 13 and 14. In station 2, the additive KoMnencnpyf- with the RS-flip-flop voltage -M according to the GB algorithm. The suppression of the crossover of gkhi is determined by the j - pattern of the impedances of the current source 7 in the LED circuit and the resistor. B. 2 Il. a you s

Description

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The invention relates to telecommunications engineering and can be used to transmit information by analog and discrete bipolar signals over a two-wire physical line.

The purpose of the invention is to reduce the level of crosstalk when duplex information is transmitted via a two-wire COMMUNICATION LINE.

Fig. 1 shows a structural electrical circuit of the system; in fig. 2 - timing diagrams that show how the system works.

The system comprises the first 1 and second 2 transceivers, the two-wire communication line 3. Each transceiver contains transmitting amplifier 4, receiving amplifier 5, first differential amplifier 6, modulated current source 7, resistor 8, first 9 and second 10 optocouplers, second 11 and third 12 differential amplifiers, first 13 and second 14 comparators, filter 15 low frequencies, block 16 rectifying, the first 17 and the second 18 attenuators. The first transceiver 1 additionally contains a synchronizer 19 and an adder 20. The second transceiver 2 additionally contains an RS flip-flop 21 and a fourth differential amplifier 22.

The system of duplex information transmission works as follows.

The signal to be transmitted is amplified by transmitting amplifier 4 (in Fig. 2a, b, arbitrary waveforms are shown transmitted by stations 1 and 2, respectively). Signal 1 is transmitted at station 1 through adder 20, and at station 2 it is directly fed to the input of current source 7, the current at the output of which repeats the waveform, while the currents of both stations go to link 3 and are mixed on resistors 8 and optocoupler LEDs 9.1 and 10.1. The oscillogram of the total current to flow in the resistors 8 is shown in FIG. 2c, the dotted line denotes the zone of the gwi of hepatitis with geograti 9.1 and 10.1. In order to output the signals of the insensitivity zone m, the synchronous generator 19 forms a voltage whose polarity coincides with the polarity of the current and resistors 8, and the amplitude is equal to the width of the insensitive-pg zone (Fig. 2d).

The voltage of the sync generator IV is summed in the adder 20 with the transmitted signal, as a result of which the current in the line is deformed in such a way that the dead zone is intersected by the shortest way step (fig.2d). As a result, at the output of the optocoupler 10, an undistorted positive half-wave (Fig. 2e) of the sum signal (Fig. 2c) is received to the non-inverting input of the differential amplifier 11, and to the second, inverting input, the signal is received positively (Fig. 2h). (Fig. 2a), which is separated by rectifier 1B and attenuator 18, serving to equalize the transmission coefficients of the two signal paths (through the optocoupler Yu, resistor 8, current source 7, adder 20, on the one hand, and through rectifier block 16 Thanks, on the other second hand). At the output of the differential amplifier 11, a positive half-wave of the received signal is formed (Fig. 2i). Similarly, the negative half-wave of the received signal is extracted.

(Fig. 2k) at the output of the differential amplifier 12 (it is inverted when passing through the diode 9.1 and rectifier unit 16). Summing up in the differential amplifier 6, both half-waves allow receiving the Mbui signal (Fig. 2b) at the output of the receiving amplifier 5 of station 1.

In a similar way, the received signal at station 2 is allocated. At the last, the voltage set by the generator 19 is compensated by the voltage produced by the trigger 21 (Fig. 2n),

Claims (1)

Invention Formula A duplex information transmission system comprising two transceiver stations connected by a two-wire communication line and consisting of a transmitting and receiving amplifier of the first differential amplifier, the first attenuator and a resistor, in order to reduce the level of crosstalk during duplex transmission of information over a two-wire communication line, a modulated source is inputted into each transceiver station, the output of which is connected to the two-wire power line and to the first outlet of the resistor, the first the second optocoupler, the rectifier, the second attenuator, the first and second comparators, the second and third differential amplifiers and a low-pass filter, in the first transceiver station - serially connected synchro generator and adder, and in the second transceiver station - serially connected trigger and fourth differential amplifier, the output of the transmitting amplifier in the first transceiver station is connected to the input of the output unit and to the second input of the adder, the output of which is connected to the input of the modulated source In the second transceiver station, to the inputs of the rectifier unit and modulated current source, the first and second outputs of the rectifier units of each transceiver station are connected to the input of the first and second attenuators, respectively, the outputs of which are connected to the first inputs of the second and third differential amplifiers, the cathode and anode of the LEDs of the first and second optocouplers are connected to the second output of the resistor, the anode and cathode of the photodiodes of the first and second optocouplers are connected to the ground bus, the outputs The first and second optocouplers are connected to the inputs of the first and second comparators, respectively, and to the second inputs of the second and third differential amplifiers, respectively, the outputs of which are connected to the first and second inputs of the first differential amplifier, respectively; whose output is connected to the input of the receiving amplifier, and the outputs of the first and second comparators are connected respectively to the first and second In the second transceiver station, the output of the first differential amplifier is connected to the second input of the fourth differential amplifier, the outputs of the first and second comparators are connected to the corresponding inputs of the RS flip-flop, and the output of the fourth differential amplifier is connected to the input of the lower filter from which the output is connected to input receiving amplifier. L / L