SU66585A1 - Device for multichannel telegraph transmission - Google Patents

Description

There is a known method of multichannel telegraphy with transmission over a separate channel of oscillations of the control frequency used at the reception site to automatically adjust the level of the received telegraph signals. There is also known a method for correcting the duration of telegraph signal pulses by applying to the output device a constant voltage, proportional to the level of received signals, in counterphase with received telegraph signals, to the output device.

The proposed device uses the features of both of these methods. For this, the straightened voltage of the control channel is used as the bias voltage of the callotrotron.

FIG. 1 shows a skeletal diagram of a multichannel telegraphy system between stations A and B; in fig. 2 - skeleton receiver circuit.

The working frequencies modulated by telegraph signals are transmitted from the transmitting station to the receiving station in the usual way using transmitting and receiving band-pass filters. In addition, the control frequency oscillations are transmitted in the same way with a constant level.

The transmitting part of the equipment (Fig. 1) is fundamentally no different from the usual frequency wiring equipment and consists of transmitting frequency generators (by the number of channels), TM telegraphic modulators and NF transmitting filters.

The receiving part of the equipment consists of the receiving filter of the PRF (according to the number of transmitted frequencies) and the NR receivers (according to the number of operating frequencies). Each receiver has two pairs of input terminals (Fig. 2): one for the control frequency (i.k. h.) And the second for the operating frequency (i.c..ch.). Clips in vh.k.ch. all receivers are connected to the output of the receiving filter of the control frequency, and the switching on of the receivers can be parallel, serial

No. 66585

or combined. Clamps in R. Each receiver is connected to the outputs of the corresponding operating frequency receiver filters. A receiver is a symmetrical device consisting of an amplifier, a rectifier and a relay. In the amplifier, the operating and reference frequencies are independently amplified and rectifier is also independently rectified. Straightened voltages 1 / p and V are applied with opposite signs to the resistance R, at the terminals b of which the total voltage V acts. This voltage is applied to the input of the relay. The gain of the working and control frequencies in each successor is adjusted so that there is equality;

Then the resulting voltage V acting on the terminals ab of the resistance R will be bipolar signals without any pole prevailing. With the passage of transmitted frequencies in the common path, they all undergo the same attenuation. Therefore, with changes in and oscillations of the latter, the ratio of currents and voltages of frequencies remains unchanged. In the future, when the residual attenuation of the common transmission path changes, relation (1) does not violate and at the terminals ab of the resistance R there is no predominance of voltage.

An electronic relay with snap (callarotron), whose circuit and principle of operation are well known, has the following properties.

Telegraph signals at the output of the callerotron are direct current signals and retain a constant amplitude and rectangle shape with very significant (on the order of several neperov) variations in the voltage level at the input. The change of sign of these signals occurs at the moment when the voltage at the input of the callout line reaches a certain value of EUT, called the response voltage of the callotrotron. Upon reaching the input voltage VQ, a change in the sign at its output occurs instantaneously. The process of reversal of the sign is avalanche in nature and takes place independently of the further voltage changes at the input of the callarotron, unless it reaches a value of 1 / o with the opposite sign when a new reversal of the sign of the output signal occurs. Between changes in the sign of the signals, the callarotron is in a stable state.

Thus, with significant changes in the residual attenuation of the common transmission path, the telegraph signals in the local receiving chain do not change in form or amplitude; only their duration can change. The calculation of the amount of distortion in the frequency wiring channel shows that in the proposed device without special difficulties a relatively small amount of distortion of the pulse duration (up to 10%) is obtained with very significant fluctuations in the receiving level (+ 1.5 neper). In this case, the calculation provides for the most severe conditions — an instantaneous change in the level within the specified limits, i.e., in the example given, three times. With smaller or smooth changes in the level, the distortion value will be less than 10%.

Subject invention

A device for multichannel transmission of telegraph signals, in which a control channel / p 2V, (I) is used to eliminate the change in the duration of telegraph signals depending on the level of the latter.

At the end of the terminal, a calyrotron is applied to which a negative bias is applied, which is proportional to the signal, characterized in that in order to ensure the inertia-free nature, the said bias directly used is a rectified voltage of the control channel.

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