SU777848A1 - Method and device for receiving signals of two-channel frequency telegraphy - Google Patents

Description

filter bandwidths are normalized in an amplifier with an AGC having a long time constant raised to. square, re-normalized by an amplifier with an LRU with a shorter time constant, detected by an amplitude detector. The detected signals of the individual channels add up, form "push and unwrap" channels, each of which measure the interference power, form a bipolar signal, sum up the "uncoupled" and "press n" channels in pairs and decide on the sign of the transmitted parcel.

The ria drawing shows a structural electrical circuit of the proposed device, realizing, its method of adaptive reception of DnG signals.

The device of adaptive reception of signals D4T contains four channels of separate reception, each of which contains a band-pass filter 1, the first amplifier 2 with Aru, quad 5, the second amplifier 4 with AGC and amplitude detector 5. The outputs of the detectors 5 of all channels are connected in pairs to the adders 6. Device it also contains solver blocks 7, inverters and, keys y, block 10, fixing the interference level, adjustable amplifiers AND, balancing, blocks 12 and adders 13. The outputs are solved, their blocks 7 are the outputs of the device;

The device works as follows;

The signal from the output of the linear path of the radio receiving device is fed by an intermediate frequency at the input of the band-pass filters 1 of the separate reception channel. After filtering, the signal in each channel is an alternation of pause packets. This signal is amplified and normalized by the level in amplifier 2 with AGC and then fed to quadrant 3, the output voltage of which is proportional to the square of the input voltage. Rationing and squaring improve the signal-to-interference ratio in those channels where the signal is more disturbed. Repeated rationing, drying, performed in amplifier 4 with AGC, ensures the constant output voltage of the channel. Amplitude detectors 5 isolate the curvature, the intermediate frequency voltage, with the negative channel in the first channel, the negative half period, in the fourth channel - positive, and in the second and third channels both positive and negative.

From the outputs of the separate reception channels, the signal pulses and interference come to the adders 6, add up and arrive simultaneously to the signal inputs of the adjustable amplifiers 11 and the keys 9. Ha the second inputs of the keys 9 are given prohibition signals from the outputs, and their blocks 7

directly or through inverters 8. At the outputs of the keys 9, the output voltage exists only at moments corresponding to pauses. The interference level fixing unit 1U produces a control device for amplifier 11, the transmission coefficient of which is inversely proportional to the control voltage and correspondingly decreases with increasing noise in the summed channels. Block 10 is designed so that the control voltage does not depend on the duration of the parcels and pauses in the channels of separate reception.

Thus, under the influence of the rectifying voltage of the noise supplied to the control input of the adjustable amplifier AND, the voltage and signal distribution weights, which are then fed to the balancing unit 12, are weighted, balanced to a zero value, and fed to the adder 13, where linear summation of signals of all channels and the restoration of the original signal. The output signal of the adder 13 is bipolar pulses, the amplitudes of the polarities of which may be different (depending on the presence and level of interference in branch x). These arrive at decision block 7, where a decision is made about the sign of the transmitted through the given channel with the same probability of error for both states ("pressed and" released).

The proposed method and device for adaptive reception of QH signals allows to increase the noise immunity of reception under the action of various interference, which provides increased reliability of radio communications.

Claims (2)

1. The method of adaptive reception of signals of two-channel frequency telegraphy, based on the fact that the signals of frequency manipulation are divided into separate channels, B of which signals are normalized by level and detected, characterized in that, in order to improve noise immunity, the detected signals of individual channels summed up in pairs, in this way they form channels of “press and“ release, in each of which they measure the interference power, form a bipolar signal, sum up in pairs the signals of the channels “release and“ press and decide the sign of the transmitted parcel. 2. A device for implementing the method of claim 1, comprising in each channel a serially connected bandpass filter, a first amplifier with automatic gain control (AGC), a quad, a second amplifier with AGC and an amplitude detector, characterized in that adders are entered into it , decision blocks, inverters, adjustable amplifiers, balancing blocks, interference level fixing blocks and keys, the first inputs of which are connected to the outputs of the corresponding adders and the first inputs of adjustable amplifiers, the second inputs of which are connected enes with outputs of corresponding interference level fixing blocks whose inputs are connected to outputs of keys, wherein the outputs of balancing units are connected to respective inputs of adders, whose outputs are through decision blocks, they are connected to the second inputs of some keys and to the inputs of the inverters, the outputs of which are connected to the second inputs of other keys, and the outputs of the amplitude detectors of each channel are connected to the inputs of the corresponding adders. Sources of information taken into account during the examination 1. V. V. Palshkov. Radio receiving kSv zy, 1965, p. 508--519 devices, M., (prototype).