Signal processing circuit for an FM signal receiver
US4219778A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 21, 1979 |
| Grant date | Aug 26, 1980 |
| Priority date | — |
| Expiry date | Feb 21, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03J3/12
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A signal processing circuit for an FM signal receiver suitable for constructing in an integrated circuit is disclosed. The signal processing circuit comprises a differential amplifier circuit receiving first and second demodulated signals of the frequency modulated signal and providing first and second output signals. A current switching circuit has a first input point for receiving the second output signal of the amplifier and a second input point for receiving the output of a constant current source. The current switching circuit switches current paths from the first and second input points to first and second output points in response switching control inputs. A first current mirror has an input point coupled to the second output point of the current switching circuit and an output point coupled to the first output signal of the amplifier circuit. A second current mirror has an input point coupled to the first output point of the current switching circuit, a first output point coupled to the output point of the first current mirror and a second output point coupled to an output terminal. A null-centered indicator is connected between a reference voltage terminal and the junction…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.