SU886286A1 - Information receiving-transmitting method - Google Patents

Description

(54) METHOD OF RECEPTION-TRANSFER OF INFORMATION

I

The invention relates to communication and can be used in organizing the transfer of information in duplex mode of operation over two-wire telephone channels with frequency division of subchannels.

A method of receiving and transmitting information is known, which consists in generating frequencies fj and fj in transmission of signals in accordance with the information transmitted and transmitting these signals over the channel, and at reception — amplifying received signals, filtering, limiting them and frequency detection t 1However, the known method does not provides minimal information distortion.

The purpose of the invention is to reduce information distortions.

To achieve this goal in the method, the transmission of signals in the second subchannel is carried out at frequencies of 3fi and 3fi, 3. reception in the first subchannel

performed at frequencies of 3f, and 3f ', and frequency detection of both subchannels is performed non-simultaneously.

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

The device contains a frequency-modulated oscillator 1, a filter 2 of the first subchannel, an amplifier 3 transmission, a differential unit 4, an amplifier 5 reception, a filter 6 of the second subchannel, an amplifier-limiter 7, a frequency detector 8 and a switch 9.

The device works in the following way ..

Claims (1)

The frequency modulated oscillator 1 generates the characteristic frequencies of the first or second subchannel. Filter 2 in transmission path 4 serves to convert rectangular parcels into sinusoidal ones that are suitable for transmission over the Sleep communication channel (not shown). Amplifier 3 38 amplifies the currents of transmitted frequencies to the level required for transmission to the communication channel. The differential unit 4 provides a transition from a four-wire to a two-wire channel line. The amplifier 5 amplifies the receiving frequency currents coming from the communication channel. Filter 6 serves to separate the current frequencies of the second subchannel. Amplifier limiter 7 amplifies the amplitude limiting of the currents of received frequencies, converting them from sinusoidal to rectangular pulses. Frequency detector 8, tuned to the frequencies of the second subchannel, detects the frequency-modulated received signal and is common to both subchannels. In the case of reception on the second subchannel, the frequency detector 8 extracts the currents of the main frequencies to which it is tuned, and when receiving on the first subchannel, the currents of the third harmonic of the characteristic frequencies of the first subchannel. As a result, in the first subchannel, the edge distortion due to the low carrier frequency is reduced. The commutator 9 performs the switching of filters 2 and 6 when the frequencies of the subchannels transmit and receive are changed. The proposed method allows reducing edge distortions and simplifies the device for receiving and transmitting information. The method of receiving and transmitting information, which consists in generating frequencies f and fj on a signal transmission in accordance with the information transmitted and transmitting the signals over the channel, and receiving - amplifying the received signals, filtering, limiting them and frequency detection, which is different. By the fact that, in order to reduce information distortions, before 51, the signals in the WTO.ROM subchannel are performed at frequencies 3f) and Sf and reception in the first subchannel is performed at frequencies 3f, and Sf, and Substrate simultaneously. Sources of information taken into account in the examination 1. German Patent K 1285502, cl. 21 a 9/02, pub. 1968 (prog type).