SU1252962A1 - Device for discriminating frequency-shift keyed signals - Google Patents

Abstract

This invention relates to the field of communications. The purpose of the invention is to increase the detection accuracy. The device contains multipliers (D) I and 2, integrators 4 and 5, a decisive unit 6, a master oscillator 9, a driver 10 reference frequencies. The goal is achieved by introducing P 3, bandpass filter 7 and phase detector 8. The device, selecting the synchronization signal from the information one, adjusting the oscillator 9 and providing the in-phase reception of 1x and reference oscillations, performs the detection of frequency-manipulated signals equivalent to the synchronous detector to vania. 1 IL. I (L with

Description

The invention relates to communications and can be used on radio routes when receiving frequency-manipulated signals.

The purpose of the invention is to improve the accuracy of detection.

The drawing shows the structural-electrical circuit of the device.

The device contains the first 1, second 2 and third 3 transponders, the first 4 and second 5 integrators, the decisive unit 6, the band-pass filter 7, the phase detector 8, the master oscillator 9 and the driver 10 of the reference frequencies.

The device works as follows.

In the absence of signals at the signal input with a frequency of CJ, or CO2 solutions, unit 6 is in its original stable state, since the levels at the output of the first 4 and second 5 integrators are in this case approximately the same and small.

When a signal appears at a signal input with a frequency to, in phase with the reference frequency s, supplied to the control input of the first multiplier 1, or a signal with a frequency o) in phase with the reference frequency d) supplied to the control input of the second multiplier 2, At the output of the decision block 6, there will be a voltage whose sign is determined by the difference in the levels of the signals at the outputs of the first 4 and second 5 integrators. Moreover, when a signal with a frequency Co arrives at the signal input, the signal level at the output of the first integrator 4 is significantly higher than the signal level at the output of the second integrator 5 and the voltage sign at the output of decision block 6 will be one, and when the signal input at the signal input with frequency 0 The signal at the output of the first integrator 4 is significantly less than the level of the signal at the output of the second integrator 5 and the voltage sign at the output of this unit 6 will be different.

This is ensured by using as an integrator 4 and 5 low-pass filters with a cutoff frequency UCD of 1 Hz and using as a decisive block 6 a level comparison circuit, for example, a comparator.

The frequency of the received and reference frequencies is provided by a third multiplier 3, a band-pass filter 7, a phase detector 8, a master oscillator 9, and a driver IO of the reference frequencies. If any of the frequencies are present (O, or 2 3 signal input, the output of the third multiplier 3 will always have a difference component in the frequency spectrum

O) + CO2

incoming Q, (or Ы): IW, -Wil

W (- -,

reference frequency

s

and

W,

2 2

 + Wt | co,

..

This component

Q, - COt

got it

bandpass filter 7 and is used as a synchronization signal, which is fed to the first input of the phase detector 8 and compared with a signal of the same frequency that arrives at the second input of the phase detector 8 from the third output of the reference frequency generator 10, and the result of the comparison the detector 8 to the control input of the master oscillator 9 is adjusted by the master oscillator 9.

Claims (1)

Thus, the proposed device, extracting the synchronization signal from the information one, adjusting it to the master oscillator and thereby ensuring the same phase of received and basic oscillations, performs the detection of frequency-manipulated signals equivalent to synchronous detection. Invention Formula A device for detecting frequency-manipulated signals, comprising a serially connected first multiplier, a first integrator and a decision unit, serially connected a second multiplier and a second integrator, serially connected master oscillator and a reference frequency generator, the first and second outputs of which are connected respectively to the control inputs of the first and the second multiplier, the signal inputs of which are combined, and the output of the second integrator is connected to the second input of the decimal block Eye, characterized in that, in order to increase the accuracy of de 312529624 tecting, a post-generator was introduced into it, and the signaling and controllably connected third transient inputs of the third intermittent. the resident, the bandpass filter and the phase are connected respectively to the signal detector, the second input and the output by the first input of the first alternator are connected respectively to the third multiplier and to the fourth output of the reference frequency former and the reference input from the control input frequency. Compiled by O. Andrushko Editor A. Kozoriz Tehred I. Veres Proofreader A. Znmokos Order 4632/58 Circulation 624 Subscription VNIIPI USSR State Committee on affairs of inventions and otkryggy 113035, Moscow, Zh-35, Raushsk nab., d.4 / 5 Production and printing company, Uzhgorod, Projecto st., 4