Tuned inductorless active phase shift demodulator
US4628272A · kind A · utility
10Cited by
16References
23Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 1, 1984 |
| Grant date | Dec 9, 1986 |
| Priority date | — |
| Expiry date | Oct 1, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D2200/0096
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An inductorless quadrature demodulator for frequency modulated signals is disclosed. A limited FM signal is passed through an active filter (26) and a phase shift network (30) to produce a quadrature signal. The limited FM signal is compared with the quadrature signal in an EXCLUSIVE OR gate (24) and then low pass filtered (36) to obtain recovered audio. The active filter (26) includes a transconductance amplifier (60) whose center frequency can be adjusted by appropriate adjustment of the amplifier's bias current. The bias current is temperature compensated to allow operation of the demodulator over a wide temperature range.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.