Analysis of Nonlinear Distortion in Direct Sampling Mixers

Recently, improvement of CMOS process has made reconfigurable, single-chip digital transceiver possible. In a digital transceiver, direct sampling mixer (DSM) is a circuitry that performs down-conversion, filtering, and decimation. Conventionally, an analysis of DSM has been treated by replacing each procedure into linear filters. However, because DSM has a nonlinear characteristic for its amplifier and switch, detail analysis can´t be achieved by linear analysis. In this paper, we consider the nonlinear characteristic of DSM and show the simulation results of nonlinear distortion; AM/AM and EVM.