CODED SPEECH TRANSMISSION AND RECEPTION METHOD Russian patent published in 2004 - IPC

FIELD: voice signal conversion and transmission. SUBSTANCE: maximum possible frequency band of source signal ranging between 0 and 2400 Hz is transferred in frequency band of 300- 2700 Hz where frequencies over 2400 Hz produce utmost impact on intelligibility of speech. In addition digitization is effected at frequency equal to double width of transmitted spectrum and not at double highest frequency of this spectrum so as to enable shifting spectrum of signal transmitted to high-frequency region. To this end voice signal spectrum of 300-2700 Hz is first shifted toward low frequencies through f_int = 1500 Hz equal to intermediate frequency of frequency band allocated for voice signal transmission and for low-frequency filtering of this signal to obtain its common-mode and quadrature components which have highest frequency of 1200 Hz and are digitized at frequency of 2400 Hz, converted into sequences of phases and amplitudes in polar coordinate system, separately scrambled, converted into single time flow of readings, passed through analog-to-digital converter, and then transmitted over standard telephone communication channel. EFFECT: enhanced quality and intelligibility of speech. 1 cl, 2 dwg