A New Control Law for N-Path Mixer Switches Enhancing Harmonic Rejection

This paper presents a novel methodology to enhance harmonic rejection in N-Path Mixers thanks to a dedicated switch control law. The proposed method reduces the effective local oscillator distortion, in order to limit unwanted harmonics appearance at the mixer output. This is achieved by using a non-conventional control of the N-path mixer switches, based on level crossing sampling techniques. The methodology strength is its ability to be used with any N-path mixer, whatever the number of paths. The article details how to optimally design the switch control. To validate the effectiveness of the proposed approach, simulations have been conducted on 4-path and 8-path mixers and compared to the corresponding conventional N-path mixers. This analysis shows significant improvements in terms of harmonic rejection thanks to this new methodology.