SU387532A1 - DEVICE FOR DETECTION OF DISCRETION OF DISCRETION INFORMATION IN THE COMMUNICATION CHANNEL FOR RECEIVERS OF FREQUENCY-MANIPULATED - Google Patents

Description

one

The invention relates to the field of transmitting discrete information with Pommod methods of frequency modulation, in particular, to devices for receiving such information, in which information distortion detection circuits in a communication channel are used to increase the reliability of received signals.

A device for detecting distortion of discrete information in a communication channel for receivers of frequency-manialed signals is known, consisting of a forming node, the output of which is simultaneously connected to the inputs of the information channel and, according to the number of frequencies used, control channels.

When receiving information, one of the most significant factors is its reliability, therefore, devices with high sensitivity must be used to detect interference in the communication channel.

The aim of the invention is to increase the fidelity of the reception. For this, the output of the forming unit is connected to the input of additionally introduced signal quality detectors, the outputs of which are combined by the OR circuit.

The drawing shows a block diagram of the proposed device.

It contains forming Zzel /, filter 2 of the second harmonic signal, detector 3,

AND

4 low-pass filter, threshold node 5 and the scheme "OR 6.

The device receives the received signal from the receiver input circuits on the forming node J. The forming node amplifies the signal, limits it to the amplitude and forms it in a pulse sequence. The fronts of the pulses correspond to the moments of the crossing zero input signal.

With a purely sinusoidal signal, the duty cycle is equal to two. Such a pulse sequence contains only odd harmonics of the fundamental frequency in its spectrum. In the presence of distortions

varies, with even harmonic components appearing in the spectrum of the pulse sequence. The highest level has the second harmonic signal. Filter 2 of the second harmonic extracts it from the spectrum. Signal

detected from the output of this filter, passes through the low-pass filter 4 and enters the input of the threshold node 5, the triggering of which is a signal that prohibits reception. Depending on how many frequencies

used to transmit discrete information, the number of signal quality detectors consisting of the second harmonic filter of the corresponding frequency, the detector, the low-pass filter and the threshold device is determined.

The outputs of the signal quality detectors are combined with the scheme “OR. Triggering any one of them will be a signal that prohibits reception.

The greater sensitivity of the proposed device in comparison with the device using the temporal control method follows from the calculations of the effective values of the second harmonic voltage and the pulses produced when comparing the time for the same duty cycle values.

Subject invention

A device for detecting distortion of discrete information in a communication channel for adopting frequency-controlled signals, consisting of a forming node, the output of which is simultaneously connected to the inputs of information and, but the number of frequencies used, control channels, in order to increase the reception accuracy, the output of the forming unit is connected to the input of additionally introduced signal quality detectors consisting of series-connected second harmonic filter, detector, low-pass filter and a threshold node, with the outputs of the signal quality detectors combined by the “OR.