Linearized integrated FM demodulator using a plurality of cascaded all- pass filters or a bessel filter

摘要

An approach for demodulating a frequency-modulated signal involves processing a frequency-modulated signal with a phase shifter network to provide a demodulated signal that has a relatively constant amplitude around the center frequency of the frequency-modulated signal and that exhibits a relatively linear phase change over an operational frequency range. Embodiments of the invention include a phase shifter network, using N number of cascaded all-pass filters, that receives as an input a limited amplitude signal and outputs a phase-shifted limited amplitude signal that is mixed with the limited amplitude signal. The phase shifter network may also comprise a low-pass bessel filter.