Analysis and Measurement of Cross Modulation Distortion in WCDMA Receivers

Abstract

Due to non linearity of the front end RF components in a WCDMA Receiver, the modulation of the leaked transmitter (TX) signal can get transferred to a blocker, resulting in cross-modulation. If the blocker is close to the desired channel, the cross-modulation spectrum would contaminate the desired channel. Previous published work has analyzed cross-modulation but only for the cases when the leaked TX signal has one or infinite number of physical channels. In this paper, we perform more exhaustive analysis, and derive a closed form expression for the distortion as a function of a generic (N) number of channels in the leaked TX signal. This analysis is also supported with measurements on a WCDMA chip.