METHOD OF DEMODULATION OF SIGNALS WITH RELATIVE PHASE-SHIFT KEYING AND DEVICE FOR REALIZATION Russian patent published in 2001 - IPC

FIELD: communication equipment. SUBSTANCE: method can be used for reception of discrete information signals with instability of signal frequency caused by presence of great value of Doppler frequency shift in communication channel in particular. Input phase-shift signal is resolved into cophasal and quadrature components relative to central frequency of range of input signals, each mentioned components is filtered in band of low frequencies equal to half-width of range of frequencies of input signals. Both filtered signals are delayed by half length of signal. In this case first component mentioned above is formed as result of summation of product of filtered cophasal signal with delayed filtered cophasal signal and product of filtered quadrature signal with delayed filtered quadrature signal. Second above-mentioned component of signal is formed as result of difference of product of delayed filtered cophasal signal with filtered quadrature signal and product of filtered cophasal signal with delayed filtered quadrature signal. Method is realized by device incorporating eight multipliers, common signal source 3, phase inverter 4, five storage elements of half-length of bit 5, 8, 9, 15, 22, two integrators 6, 7 with reset, three adders 12, 13, 19, solving unit 14, synchronizer 16, two low-pass filters 17, 20, subtracter 24. Common signal source presents generator whose frequency is equal to central frequency of range of input frequencies of signal, with width of band of low-pass frequencies equal to half-width of range of input frequencies. EFFECT: increased noise immunity thanks to exclusion of additional high-frequency noise components emerging in prototype after multiplication operations which come before integration with reset and thanks to reduced power of other noise components prior to integration with reset with maintenance of invariance to frequency of received signal. 3 cl, 2 dwg