| 摘要 |
A process for the demodulation of an amplitude modulated signal composed of two suppressed carriers, at a same frequency F and in phase quadrature, which are respectively modulated by two modulation signals, the modulated signal being preceded by a reference signal at frequency F, by sampling the reference signal and the modulated signal, according to a frequency m.F (m being an integer); determining a polar angle psi t of a rotating vector representing the reference signal, at time t, by calculating: <IMAGE> where x(t) and x(t-(1/4F)) are the values of two successive samples of the reference signal; determining polar coordinates ( rho t, theta t) of a rotating vector representing the modulated signal, at time t, by calculating: <IMAGE> <IMAGE> where y(t) and y(t-(1/4F)) are values of two successive samples of the modulated signal, calculating gamma = theta t- omega t- phi o, where phi o is the phase displacement between the reference signal and one of the carriers, calculating alpha = rho t.cos gamma beta = rho t.sin gamma and generating two signals whose instantaneous amplitudes are alpha and lambda beta . |
