SU866776A1 - Demodulator of discrete phase -modulated signals - Google Patents

Description

(54) DEMODULATOR OF DISCRETE PHASE-SUSPENDED SIGNALS

I

The invention relates to telecommunications and can be used in devices transmitting digital information over communication channels using phase modulation.

Known demodulator discrete phase-modulated signals, containing a band-pass filter, the output of which is. pogo connected to the input of the limiter, a pulse generator, an adder, an element OR, a trigger and an inverter l.

However, the known demodulator has a low noise immunity.

The purpose of the invention is to improve noise immunity.

To do this, a discrete phase-modulated signal containing a band-pass filter whose output is connected to the limiter input, a pulse generator, an adder, an OR element, a trigger and an inverter is inserted into the demodulator, a reverse counter, a switch, a frequency divider and registers, whose outputs are through a switch

The reader is connected to the inputs of reversible meters, the outputs of which are connected to the corresponding inputs of the Trigger and the element SHW, the output of which is connected via a frequency divider to the first input of the cy e4a toopa; registers, the other inputs of which are connected respectively to the outputs of the limiter and the inverter, to the input of which the output of the limiter is connected.

15

The drawing shows a structural electrical circuit of the proposed demodulator.

Claims (1)

The demodulator of discrete phase-modulated signals contains a polovial filter 1, limiter 2, two registers 3 and 4, an inverter 5, a generator of 6 pulses, a switch 7, two reversible counters 8 and 9, a trigger 10, an element OR 11, a frequency divider 12, an adder 13, The demodulator works as follows. The received signal, pass bandpass filter 1 and limiter 2, is fed to the input of register 3 and through the inverter 5 to the input of register 4 The input phase-stimulated signal is read by polling read pulses from pulse generator 6, registers 3, A and switch 7 are converted into reversing count pulses counters 8, 9. The pulse frequency of the interrogation pulse generator 6 is many times greater than the frequency of the carrier oscillation of the input phase-modulated signal and is determined by the counting factor of the reversible counters. During the duration of sending one character of the input phase-modulated signal, one of the reversible counters operates in the summation mode, and the other in the subtraction mode. For the duration of sending another sign of the counter work in opposite modes. The control of the counting mode of reversible counters is performed by converting the input phase-modulated signal into the counting pulses of the reverse counter by applying pulses from the pulse generator 6 to the inputs of the forward or reverse counting modes of the reversing counters 8 and 9, depending on the sign of sending the input-phase-modulated signal. The pulses at the output of the reversible counters reset the counters to the initial state and switch trigger 1 to the appropriate state. At the output of the element OR 11, after the logical addition of two pulse sequences with the output of reversible counters, a continuous pulse sequence is formed with a frequency equal to twice the frequency of the carrier wave. 4 With the output of frequency divider 12, one of the inputs of the adder 13 receives a reference signal with a frequency equal to the frequency of the carrier wave. At the output of the adder 13 we get the demodulated signal. Thus, the introduction of new blocks increases the noise immunity of the proposed demodulator of discrete phase-modulated signals. DETAILED DESCRIPTION OF THE INVENTION A discrete phase-modulated signal demodulator comprising a band-pass filter whose output is connected to a limiter input, a pulse generator, an adder, an OR element, a trigger and an inverter, characterized in that, in order to improve noise immunity, reversible counters, a switch, a frequency divider and registers, the outputs of which through the switch are connected to the inputs of reversible meters, the outputs of which are connected to the corresponding inputs of the trigger and the OR element, the output of which through the divider is h Frequency is connected to the first input of the adder, to the second input of which the output of the trigger is connected, the output of the pulse generator is connected to the corresponding input of the switch and one of the inputs of the registers, the other inputs of which are connected respectively to the outputs of the limiter and inverter, to the input of which the output of the limiter is connected. Sources of information taken into account in the examination 1. Shl Bersky V. I. Fundamentals of technical communication of discrete messages M., Svy, 1973, p. 229-239 (prototype). w