METHOD FOR BROADCASTING FREQUENCY-MODULATED STEREO RADIO SIGNAL IN UHF AND VHF BANDS IN PILOTTONE SYSTEM Russian patent published in 2004 - IPC

FIELD: radio broadcast. SUBSTANCE: method includes generation of total signal from stereo signal transmitted over left- hand and right-hand channels which is basic single audio signal; generation of narrow-band coded control signal that carries information about differences in left-hand and right-hand channel signals; modulation of pilot-tone signal by this narrow-band coded control signal; supply of basic single audio signal to first input of frequency modulator; transfer of modulated pilot-tone to second input of frequency modulator; and transmission of frequency-modulated signal. On receiving end basic single audio signal is separated and conveyed to two controllable-response filters; modulated pilot-tone is also separated, applied to decoder that separates narrow-band coded control signal to change frequency response of filters thereby ensuring recovery of stereo signal. This method provides for reducing high-frequency signal band by approximately one third which enables disposing greater number of stations in frequency band allocated for broadcasting. EFFECT: essentially reduced frequency bandwidth and high-frequency signal band. 1 cl, 2 dwg