FM Modulator using an oscillating feedback circuit
US4568892A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 21, 1984 |
| Grant date | Feb 4, 1986 |
| Priority date | — |
| Expiry date | Mar 21, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03C3/00
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A frequency modulating circuit for modulating a carrier signal by a modulating signal is disclosed which includes a band-pass filter of biquad type having a first integrating circuit and a second integrating circuit, an output of the first integrating circuit being supplied to an input terminal of the second integrating circuit and an output of the second integrating circuit being supplied to an input terminal of the first integrating circuit and a second input terminal of the second integrating circuit, and a limiting amplifier circuit supplied with the output signal of the band-pass filter and the output thereof being positively fed back to the band-pass filter. In this case, the modulating signal is supplied to the first and second integrating circuits such that the center frequency of the band-pass filter is linearly controlled by the modulating signal whereby a frequency modulated signal modulated by the modulating signal is led out of the output terminal of the second integrating circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.