this invention discloses a demodulation method . the method includes steps of : a ) receiving a modulated input signal having an input signal frequency . b ) generating a first switch control signal at a first switching frequency substantially equal to the input signal frequency . c ) generating a second switch control signal having the same frequency as the first switch control signal and having a phase that is approximately 90 degrees different from a phase of the first switch control signal . and d ) controlling at least two switching circuits with the first and second switch control signals for obtaining at least two sets of sampled amplitudes of the input signals for generating switching output signals for each of the switching circuits defined by subtracting the sampled amplitudes when the first switch control signal is high by the sampled amplitudes when the first switch control signal is low for each of the switching circuits to generate demodulated output signals for the modulated input signal .