Spurious mixing of off-channel signals in a wireless receiver and the choice of IF

Abstract

Circuit nonlinearity and LO harmonics can cause large interferers to translate on to the same intermediate frequency as the desired channel. The mechanisms responsible for spurious mixing, which are distinct from intermodulation distortion, are analyzed and catalogued. The analysis leads to an optimal choice of IF for a fully integrated 900 MHz GSM receiver that resists all blockers.