PERIODIC TIME-VARYING NOISE IN CURRENT-COMMUTATING CMOS MIXERS

An analytical approach based on linear periodic time-varying theory, is developed to analyze the noise characteristics of current-commutating CMOS mixers. Based on the derived transfer functions with memory effect of tail capacitance, the frequency-dependent noise transforming factors for individual stages in the mixers are numerically computed to rigorously describe the noise output. A unified noise expression considering both the thermal noise and the flicker noise is proposed. It enables the noise analysis of the mixers particularly for a high LO frequency with different IF characteristics, and is verified by measurements.