Demodulator circuit for frequency-modulated signal
US4264867A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 4, 1979 |
| Grant date | Apr 28, 1981 |
| Priority date | — |
| Expiry date | Jun 4, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/04
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An FM demodulator circuit particularly suited for construction as an integrated circuit is disclosed. Circuitry which may also serve the function of an intermediate frequency amplifier and limiter shapes the input FM signal into two rectangular waves having opposite phases which are applied to the bases of first and second transistors. First and second constant current sources supply substantially constant currents to the emitters of the first and second transistors, respectively, and a capacitive element is connected between the emitters of the first and second transistors. An adder circuit adds the collector outputs of the first and second transistors, and the added output is supplied to a low-pass filter to derive an analog output.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.