METHOD OF DEMODULATING PHASE MODULATED RADIO-FREQUENCY SIGNALS AND DEVICE TO THIS END Russian patent published in 2009 - IPC H03D3/26 

FIELD: physics.

SUBSTANCE: invention can be used for demodulating phase-shift keyed and phase modulated (PM) signals. Demodulation takes place between the source of phase modulated radio-frequency signals and a low-frequency load and is carried out using a four-terminal network, a bipolar nonlinear element and a low-pass filter. The phase modulated signal is converted to an amplitude-phase (AP) modulated signal. The spectrum of the amplitude-phase modulated signal is decomposed to high- and low-frequency components using the nonlinear element (NLE). Using the low-pass filter, the information low-frequency (LF) signal is separated, amplitude of which varies according to the law of variation of the phase of the phase modulated input signal. The bipolar nonlinear element is connected between the output of the signal source and the four-terminal network (FTN) into a transverse circuit. The four-terminal network is made from at least three reactive impedors, parametre values of which are chosen such that, the left slope of the amplitude-frequency curve is formed, by providing for the required value of the modulus m₂ of the transmission coefficient of the high-frequency (HF) part of demodulation (DM) in the second state of the nonlinear element, defined by one of the extreme values of the amplitude of the amplitude-phase modulated signal. Conversion of the phase modulated signal to an amplitude-phase modulated signal takes place by transmitting the phase modulated signal to the left-side slope of the amplitude-frequency curve. The value of the modulus m₁ of the transmission coefficient of the high-frequency part of demodulation in the first state of the nonlinear element is chosen from the condition of physical realisability of the four-terminal network. The low-frequency component of the amplitude-phase modulated signals is transmitted to an integrating circuit.

EFFECT: provision for demodulation without using a reference generator and a parallel oscillatory circuit with conversion of phase modulate signals to amplitude modulated and phase modulated signals using the high-frequency part of demodulation at given amplitude modulation depth.

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