FM demodulation circuit
US4884037A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 19, 1988 |
| Grant date | Nov 28, 1989 |
| Priority date | — |
| Expiry date | Jul 19, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D2200/0039
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A FM demodulation circuit contains an analog-to-digital converter which converts an inputted frequency-modulated (FM) signal into a digital signal of one bit at a timing based on the predetermined clock signal and a differentiation circuit which differentiates the digital signal to thereby output a pulse train whose pulse density is in proportion to a frequency of the inputted FM signal. When the pulse train is supplied to a low-pass filter, the pulse train is converted into an analog signal, which is outputted as a demodulated signal. When the pulse train is supplied to a decimation circuit which includes a weight function generating portion and an accumulator, weighted function values are sequentially accumulated based on the level of the pulse train in the predetermined period so that the demodulated signal can be obtained in the form of a linear pulse code modulated (linear PCM) signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.