Digital FSK demodulator with automatic offset cancellation
US5436590A · kind A · utility
12Cited by
5References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 25, 1994 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Aug 25, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/064
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A digital FSK demodulator used in e.g. a telephone loop produces unequal amplitudes in detected mark and space tones. The inequality or offset must be cancelled so that a proper timing signal can be recovered from the FSK signal. The demodulator includes a digital compensation circuit for offset cancellation in which peak amplitudes of digital 0 and digital 1 signals are continuously monitored. The peak amplitudes are then averaged to obtain an offset estimation which is subtracted from the output of the demodulator for offset compensation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.