RECEIVER WITH LEVEL-BASED CHARACTER DEMODULATOR Russian patent published in 2000 - IPC

FIELD: radio engineering. SUBSTANCE: receiver of frequency-shift keyed signal with zero intermediate frequency has unit for generation of demodulated modulation signals as series of narrow pulses, which repetition frequency is greater than repetition frequency of modulation signals. Said demodulator has unit for tuning threshold value for character detection depending on representation of pulse type of frequency deviations, which may differ due to shift between local oscillator frequency f_L and nominal carrier frequency transmitter f_C. Unit for tuning threshold value for character detection has unit for measurement of peak deviation of instantaneous frequency representation and difference between peak deviations, which are proportional to shift between central frequency of transmitted signal and local oscillator frequency. In addition, said unit has unit for setting character detection level with respect to middle deviation, in case of two-level signal, or set of character detection levels, in case of M-level signal. EFFECT: possibility to compensate partial frequency shift between frequency of transmitting center and local oscillator of receiver. 10 cl, 15 dwg