Method and circuit for converting frequency-modulated signals through at least one intermediate frequency into low frequency signals
US4885801A · kind A · utility
8Cited by
9References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 23, 1987 |
| Grant date | Dec 5, 1989 |
| Priority date | — |
| Expiry date | Oct 23, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/005
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A mixer mixes received frequency modulated signals with a frequency provided by a voltage controlled oscillator to generate intermediate frequency signals. The intermediate frequency signals are filtered by a filter and input to a demodulator to generate low frequency signals. A control voltage is derived from the demodulator to control the resonant frequency of the filter in response to the frequency shift of the intermediate frequency signals. A phase rotator is coupled between the demodulator and the oscillator to phase rotate the control voltage of the oscillator. In a preferred embodiment, the phase rotator is an inverter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.