Patent ID: 6137353
Filing Date: 2000-10-24
Classification: H03D

Abstract:
A demodulator for processing a frequency-modulated input signal and providing a demodulated output signal, the demodulator comprising:a limiter responsive to a frequency-modulated input signal for providing a limited-amplitude signal having a predetermined amplitude;a phase shifter network coupled to the limiter and including a plurality of cascaded filters each providing a predetermined phase shift at a center frequency and operating in a linear region, the phase shifter network being responsive to the limited amplitude signal to provide a phase-shifted limited amplitude signal having a phase shift equal to the sum of the phase shifts of the plurality of filters; anda signal mixer coupled to both the limiter and the phase shifter network, the signal mixer being responsive to both the limited amplitude signal and the phase-shifted limited amplitude signal to generate a demodulated output signal having a limited amplitude signal component and a phase-shifted limited amplitude signal component.