Digital demodulator using numerical processor to evaluate period measurements

Abstract

A digital demodulator provides efficient demodulation of frequency modulated, pulse-width modulated, and other temporally modulated signals. Without employing an analog-to-digital converter, modulating signal information is extracted from a modulated signal as numerical information. For frequency demodulation, a high gain stage is applied to an incoming FM signal to produce a corresponding sequence of square waves. The period between zero-crossings of the square waves is accurately measured to within one clock pulse using a high-speed clock and at least one counter. Period information is then provided to a numerical processor, wherein it is at least scaled and low-pass filtered to produce a high-quality demodulated signal with a high signal-to-noise ratio.

Dependencies are inferred from the claim text.