SU1356192A1 - Zero beat frequency discriminator - Google Patents

Abstract

Invention m. used in radiolocation and radionavigation when measuring the average frequency of the signal spectrum against a background of noise with an uneven spectrum. The purpose of the invention is to reduce the zero displacement of discriminatory ha-ki when exposed to noise with an uneven spectrum. The device contains mixers I and 2, phase shifter 3, low-pass filters 4-7, differentiators 8.1-8.2p, phase detectors 9.1-9.P-I, n adjustable amplifiers 10.1-lO.n, output adder. 1 il. (L oo SP 05 with th 8.2p

Description

one .

The invention relates to a measurement technique and can be used in radiolocation and radio navigation when measuring the average frequency of a signal spectrum against a background of noise with a non-uniform spectrum.

The purpose of the invention is to reduce the zero offset of the discriminatory characteristics due to noise with an uneven spectrum.

The drawing shows a structural electrical circuit of the zero-beat frequency discriminator.

The zero-beat frequency discriminator contains the first, and 1 second 2 mixers, phase shifter 3, first 4 second 5, third 6 and fourth 7 filters, low frequencies, differentiators 8.1-8.2p, phase detectors 9.1 9.P + 1, n adjustable amplifiers 10.1-10. P., the output adder 11.

Frequency discriminator zero; beating works as follows.

The input signal is fed to the first 1 and second 2 mixers, the second inputs of which receive reference frequency signals that are shifted in phase by 90 ° with the phase shifter 3. The signals from the mixer outputs go to low-pass filters 4-7, where high-frequency vibrations are filtered out. The signal from the output of the second filter 5 is differentiated by the differentiator 8.1 and sent to the phase detector 9.1, where it is multiplied with the signal from the output of the first filter 4. The signal from the output of the phase detector 9.1, consisting of a useful component proportional to the frequency detuning and a component caused by the unevenness of the noise enters the first input of the output adder 11. The signals from the output of the third 6 and fourth 7 filters are fed to the series-connected differentiators 8.2-8, n + 1. and 8.p + 2-8.2p where n and (n-1) are differentiated, respectively. The signal from the output of the differentiator 8.2 is multiplied in the phase detector 9.2 with the output signal of the fourth filter 7, then processed by the corresponding o6pa3ONf using an adjustable amplifier 10, the signal is fed to the second input of the output adder 11. The code signal of the K-th differentiator 8 k (where, ..., (n + 1)) is multiplied by

9.22

k phase detector 9.k with a signal from the output of the 8p + k differentiator and after scaling in the adjustable amplifier 10.k-1 goes to the k and the input of the output adder 11. The output of the output adder 11 is the output of the frequency discriminator of zero beat.

Claims (1)

Invention Formula Zero-beat frequency discriminator containing the first mixer and the pergg sequentially connected. A second low pass filter, a second mixer connected in series, a second low pass filter and a differentiator, the outputs of the first low pass filter and the differentiator are connected to the first and second inputs of the phase detector, respectively, the first inputs of the first and second mixers are combined and are the first frequency input a zero beat discriminator; the second inputs of the first and second mixers are connected to the input and output of the phase shifter, respectively, the input of which is the second input of the frequency discriminator n hub beats, about tl and h aa yu and so that, in order to reduce the zero offset of the discriminatory characteristic when exposed to noise with an uneven spectrum, an OUTPUT adder, connected in series to the third low-pass filter, whose input is connected to the output of the first mixer, and the first additional differentiator, the fourth low-pass filter, the input of which is connected to the output of the second mixer, n circuits, each of which contains a series-connected additional phase detector and controllable usi The first and second groups of serially connected n-1 second additional differentiators, the first group of serially connected n-1 second additional differentiators are connected between the combined output of the first additional differentiator and the first input of the first additional phase detector and the first input of the n-th additional phase j7O detector , and the second group of serially connected n-1 second additional differentiators is included 31 between the combined output of the fourth low-pass filter and the second input of the first additional phase detector and the second input of the n-th additional phase detector, codes of the second additional differentiators of the first and second rpjrnn series-connected second additional differentiators, cross-editor N. Kishtulinets Compiled by A.Kolosov Tehred M. Didyk. Proofreader S. Shekmar Order 5810/53 Edition 900 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 .. "-.-. -.-.. -. ---------- .. ---. ----. - ..-------- - ----------- .----------------- j ---- ---- ------------ ---- Production and printing company, Uzhgorod, Projecto st., 4 561924 Me (n-l) -x, connected to the first and second inputs of the additional phase detectors, respectively, starting with. the second in (n-1) -th, while the outputs of the n adjustable amplifiers are connected to the corresponding to the inputs of the output adder, and the output of the phase detector is connected to the (n + 1) th input of the output adder.