David L Ripley, Age 871102 Ghana St, Sebring, FL 33875

5870670, Feb 9, 1999

Sep 23, 1996

8/717877

David Steven Ripley - Round Lake Beach IL
William T. Waldie - Round Lake Beach IL

Motorola, Inc. - Schaumburg IL

H04B 116

455304

An integrated image reject mixer (150) generates precise quadrature components using highly matched local-oscillator (LO) path and intermediate frequency (IF) path resistor-capacitor (RC) phase shifting networks (131, 138). Because the LO signal from a local oscillator (127) has a constant amplitude, a phase detector (136) feedback loop easily maintains an accurate ninety-degree phase difference between the quadrature LO signals (122, 124) from the LO path phase shifting network (131). Because the two phase shifting networks are matched, the feedback control signal (137) from the phase detector (136) can also be used to maintain an accurate ninety-degree phase difference between the quadrature IF signals (123, 128) from the IF path phase shifting network (138) despite the dynamically-varying amplitude of the IF signal. Thus, this image reject mixer uses only components that may be easily integrated into an integrated circuit.