SU47351A1 - Duplex device - Google Patents

Description

The invention relates to a duplex device with a cathode barrier, designed to operate without a carrier frequency. The difference from the known devices in this case is that, as a local oscillator, a quartz-stabilized transmitter oscillator of the device is used for receiving the local oscillator.

The proposed schematic diagram of the device explains the essence of the invention.

The transmitter consists of exciter 6, stabilized by quartz, preamplifier 2, modulator 3 and balanced modulator 4 (generator with the elimination of the carrier frequency). The operation of this part of the circuit proceeds in the usual way, i.e. there is an oscillation of only side frequencies in the antenna and only when there is modulation. Receiver 8 can be of any type: superheterodyne or direct amplification with a corresponding cascade.

When the radio station is operating, the transmitter and receiver are tuned to the same frequency. If there were oscillations of the carrier frequency in the transmitter antenna, the receiver could not receive any other signals for obvious reasons, but since there are oscillations in the transmitting antenna only when there is modulation, and during silence they are not present, the receiver is able to receive

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Silence signals from another station, even on the same channel.

Suppose the same radio station is received without a carrier frequency. Taking it to a regular regenerator with zero beats would be somewhat difficult. However, in this scheme, due to the combination of reception and transmission, we can use as a local oscillator, creating a carrier frequency at reception, a quartz transmitter transmitter that provides the necessary stability of the carrier frequency and good reception quality. Modern quartz stabilizers provide frequency stability with an accuracy of up to 20 periods without a thermostat. The foregoing considerations allow the use of this system at frequencies up to 3000 kilohertz (100 m). For waves 200-300 m, the possibility of this scheme is beyond doubt. Thus, the combination of transmission and reception is associated with the two functions of the quartz exciter.

If during the reception of the opposite station an employee, having the desire to interrupt, says into the microphone, he will drown out the reception. To eliminate this inconvenience, the rectifier P, which is rectified from the received call, closes the input to the transmitter in the presence of reception.

therefore, acting on the microphone does not create interference as long as the opposite station speaks. It is equally necessary, when this station says, to bar the effects on the receiver input from its own transmitter. This function is performed by a rectifier locking the input of the receiver by rectified talk voltage taken from the modulation transformer. During silence on both sides, the transmission path was cut off without any special barriers, due to the principle of operation without carrier frequency. The presence of three obstacles, with silence on both sides and during a conversation with each of the parties, makes it possible to make the transition to a two-wire line on both sides simply by adding a differential transformer 7.

In the drawing, the dotted line on the right shows the connection when working with one antenna for transmitting and receiving. The use of the proposed duplex-diode-triode lamps in the proposed schemes will greatly simplify it in terms of the number of lamps. A further development of the proposed scheme is the filtering of one sideband, which can be done by known methods.

The subject matter of the invention.

A duplex device with cathode protectors for operation without a carrier frequency on a single channel with a transition to a two-wire connection, characterized in that a quartz-stabilized oscillator generator of the transmitter of the same device is used as the local oscillator.