Digital demodulator using numerical processor to evaluate period measurements
US5159281A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 20, 1991 |
| Grant date | Oct 27, 1992 |
| Priority date | — |
| Expiry date | Nov 20, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.