SU1403386A1 - Demodulator of frequency-manipulated signals - Google Patents

Abstract

FIELD: radio engineering and ib. used in receiving devices of space communication stations. The purpose of the invention is to increase the reliability of the received information. The demodulator contains bandpass filters 1 and 2, comparators (K) 3 and 4, r-r 6 pressing frequency, r-r 7 pressing frequency. To achieve the goal, a switch of 5 frequencies of pressing and spinning, integrates 9 and level meter Biyxa 8 are entered into the demodulator. The response threshold K 3 and 4 is set depending on the magnitude of the noise voltage in the receiving path of the PI signal. This makes it possible to ensure that the reference voltage level for K 3 and 4 is vlavshe, the value of which depends only on the magnitude of the noise voltage. When the C / ffi level exceeds the noise level by the amount of the resolving paths $ K 3 and 4, a logical signal O or 1 is generated at their outputs in accordance with the received signal at the discriminator input signal au Bf. 2 cl. %

Description

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The invention relates to radio engineering and can be used in receiving devices of space communication stations,

The purpose of the invention is to increase the reliability of the received information.

Fig. 1 shows a structural electrical circuit of the proposed demodulator; in FIG. 2, the time gram.

The demodulator of frequency-manipulated signals contains the first and second bandpass filters 1 and 2, the first and second comparators 3 and 4, the com- {5 mutator 5 pressing and spinning frequencies, the generator 6 pressing frequencies, the generator 7 releasing frequencies, the meter 8 levels noise integrator 9.

The noise level meter contains 20 bandpass filter 10 and an emitter follower 11,

The demodulator works as follows.

The input frequency-manipulated 25 s. Signal (FIG. 2a) is fed to bandpass filters 1 and 2 with central press and release frequencies. In-bandpass filters t and 2 signals (FIGS. 26 and 2b) are fed to the AOR inputs of the amplitude comparators 3 and 4,

The second inputs of the (amplitude) comparators 3 and 4 receive the voltage from the output of the noise level meter (fig, 2d) after integration into the integer, grater 9 (fig, 2d).

The threshold for operation of comparators 3 and 4 is set depending on the magnitude of the noise voltage in the receive path of the FSK signal. This allows Q to provide a floating reference voltage level for comparators 3 and 4, the value of which depends only on the magnitude of the noise voltage.

When the signal level + noise above the noise level is exceeded by the resolution value of the capabilities of the comparators 3 and 4, a signal O or 1 is generated at their outputs in accordance with the signals received at the discriminator input (FIG. 2e and 2g),

These signals arrive at the first and second inputs of the switch 5 of the press and release frequencies and control the supply of signals from the (quartz) oscillators 55

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press 6 and release 7 (figs, 2i) to the output of the frequency discriminator (fig, 2k).

For synchronization, a receiver clock (not specified) is used, which uses a demodulator,

The noise level meter 8 is connected to the input of the demodulator. His work is based on allocating a frequency band between the press and release frequencies to a band-pass filter 10. From the output of the filter 10, the selected signals (noise) are fed to the input of the emitter follower 11 and after the integrator 9 the noise voltage the input of the demodulator, enters the inputs (amplitude) of the comparators 3 and 4,

Claims (1)

Invention Formula A demodulator of frequency-manipulated signals containing the first and second bandpass filters whose outputs are connected to the first inputs of the first and second comparators, respectively, the frequency generator, depressor frequency generator, while the inputs of the first and second bandpass filters are combined and are the signal input demodulator, characterized in that, in order to increase the reliability of the received information when exposed to noise interference, a click and release frequency switch, an integrator and a noise level meter are introduced a, the output of which is connected via an integrator with the second inputs of the first and. The second comparators, the outputs of which are connected respectively to the first and second control inputs of the press and release frequency switch, the first and second signal inputs of which are connected to the outputs of the pressure frequency generator and the frequency generator, respectively, the inputs of which are combined, while the noise level meter input is connected to the input of the first bandpass filter, the input of the frequency generator is the synchronization input of the demodulator, the output of which is the output of the switch of the frequency press and release. -O-i 4 fc -f l: g C :: 5 (i M B j f