FSK data demodulator
US5309113A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 28, 1992 |
| Grant date | May 3, 1994 |
| Priority date | — |
| Expiry date | Sep 28, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/1525
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An FSK demodulator for demodulating first and second baseband signals obtained from a received frequency shift keying signal, the first and second baseband signals having a quadrature relation therebetween, a lead and lag relation between the first and second baseband signals being changed in accordance with frequency shift from a carrier frequency of the frequency shift keying signal, comprises: a voltage change judging circuit for judging whether a magnitude of the first baseband signal increases or decreases within a predetermined interval; and an inverting circuit responsive to an output of the voltage change judging circuit and the second baseband signal for outputting a demodulated signal produced by inverting the second baseband signal in accordance with the output of the voltage change judging circuit. In addition, a second voltage change judging circuit and a second inverting circuit and a combining circuit for combining the results of said first and second inverting circuits may be provided to improve noise resistance. Inflection points in the baseband signal are detected to select one output from the first, second inverting circuit and the combining circuit in accordance…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.