Multiple bandwidth FM demodulator
US4441079A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 13, 1981 |
| Grant date | Apr 3, 1984 |
| Priority date | — |
| Expiry date | Oct 13, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/007
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A multiple bandwidth quadrature type FM demodulator employs a double-balanced mixer supplied with a frequency modulated IF signal directly and through one of a selectable plurality of bandpass circuits each having a different bandwidth, having a linear phase shift versus frequency characteristic and producing a 90.degree. phase shift at the IF frequency whereby to produce at the output of the mixer a signal level that varies as a linear function of frequency of the input signal, the demodulator including a bias control circuit for the mixer to establish a normalized output for all filters at full bandwidth modulation and further including circuits for establishing a signal balanced with respect to ground or other reference potential regardless of the filter employed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.