Digital Cancellation of Harmonic and Intermodulation Distortion in Wideband SAW-Less Receivers

This brief presents a digital distortion equalizer that compensates for the effects of both the harmonic mixing and intermodulation products in wideband surface acoustic wave (SAW)-less receivers. A mathematical framework is derived for analyzing signal distortion in the presence of harmonic and out-of-band interferers. This framework models a K-path SAW-less M-phase receiver, which provides sufficient front-end observations to cancel the distortion products. An adaptive minimum mean-squared error (MMSE) digital equalizer is employed to estimate the desired signal in the presence of distortion products. The MMSE equalizer jointly accounts for distortion products as well as correlated noise of the two paths. A dual-path 4-phase receiver fabricated in 130 nm CMOS process has been used to validate the distortion compensation scheme.