04944025 is referenced by 182 patents and cites 12 patents.

A direct conversion FM receiver that includes AC coupling and automatic gain control employs an offset frequency at the first local oscillator. The offset frequency prevents the frequency spectrum occupied by the signal modulation from being affected by AC coupling. The offset frequency is chosen so that it translates the frequency spectrum of the received signal outside the DC notch created in the spectrum by the AC coupling. To conserve battery supplied power, an error amplifier coupled between the output of the receiver and the first local oscillator maintains the offset frequency after it has been established by a frequency synthesizer, which is then turned off.

Title
Direct conversion FM receiver with offset
Application Number
7/229976
Publication Number
4944025
Application Date
August 9, 1988
Publication Date
July 24, 1990
Inventor
Lawrence H Ragan
Richardson
TX, US
Richard R Suter
Beaverton
OR, US
Mark R Gehring
Portland
OR, US
Agent
Klarquist Sparkman Campbell Leigh & Whinston
Assignee
AT&E Corporation
CA, US
IPC
H03D 3/18
H04B 1/16
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