Statistical analysis of second-order intermodulation distortion in WCDMA direct conversion receivers

Nonlinear spectral analysis is exploited in this brief to investigate the second-order intermodulation distortion in direct conversion receivers (DCRs) for wideband code division multiple access systems. The emphasis is on the accurate modeling of the interferer, and on the derivation of the second-order intermodulation distortion spectra. Depending on the number of code multiplexed channels, the second-order intermodulation distortion power produced in the receiver can be significantly different. It varies by 6.5 dB between two boundary cases: multichannel versus single-channel signal. The developed analysis is verified by means of experiments carried out on a 0.18-μm CMOS DCR realized for the universal mobile telecommunications system standard.