FM demodulator using injection locked oscillator having tuning feedback and linearizing feedback
US5650749A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 10, 1996 |
| Grant date | Jul 22, 1997 |
| Priority date | — |
| Expiry date | Jun 10, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03L7/093
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A demodulator circuit (100) and method for producing a demodulated signal V.sub.OUT from an input signal V.sub.IN. A frequency detection circuit (101) produces a quadrature signal V.sub.QUAD which is compared to the input signal V.sub.IN to produce a detected output signal. The phase and frequency of the quadrature signal V.sub.QUAD are responsive to a control signal I.sub.CONTROL. The demodulator circuit (100) has an output terminal (114) which provides the demodulated signal V.sub.OUT. Nonlinearity in the demodulated output signal V.sub.OUT in relation to a modulating signal is reduced by a linearizing feedback circuit (102). Automatic tuning is provided by a tuning feedback circuit (103). The output signals produced at the respective output terminals (114) and (113) of the linearizing feedback circuit (102) and tuning feedback circuit (103) are summed to produce the control current I.sub.CONTROL.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.