Design of 12-phase, 2-stage Harmonic Rejection Mixer for TV Tuners

Abstract

A two-stage 12-phase harmonic rejection mixer (HRM) for TV tuners is proposed in order to reject the local oscillator (LO) harmonics up to the ninth order. The proposed 12-phase weighing scheme can eliminate the third and ninth harmonic rejection (HR) sensitivity to the amplitude error caused by irrational numbers such as root 3 To verb this HR, the 2-stage HR circuit is designed with baseband g(m) scaling in order to save power and improve the HR ratios without calibration. The proposed HRM achieves the third to ninth worst HR ratios, more than 55 dB, according to Monte Carlo simulations. It consumes 6.5 mA under a 2.5 V supply voltage.