Universal FM receiver for mobile communications
US4835792A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 25, 1988 |
| Grant date | May 30, 1989 |
| Priority date | — |
| Expiry date | Jan 25, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J7/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A dual purpose receiver operable both on FM analog (voice) and MSK digital (data) signals has a demodulation section having a selectable time delay D.sub.1 for processing MSK digital signals and a time delay D.sub.2 for processing FM analog signals. A switch permits selection of the time delay for the demodulating mode desired. A second switch set according to how the first switch is set connects a digital processing circuit or an analog processing circuit to the output of the demodulation section. Small frequency errors due to frequency drift of the local oscillator or signal source and doppler effects can be eliminated by an automatic frequency control (AFC) circuit responsive to the output of the demodulator in the analog mode, and through a third switch responsive to a signal developed by mixing the input signal with the input signal delayed by a time delay D.sub.1, and mixing the output of that mixer with the binary output of the receiver in the MSK mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.