A 10MHz IF digitizer using a novel quadrant based swapping scheme for I, Q mismatch elimination that achieves an equivalent 65dB image rejection ratio

This paper presents a novel quadrant based swapping scheme that eliminates I/Q path mismatch for phase modulated receiver. The effectiveness is demonstrated by applying the scheme to the IF digitizer part of the receiver. The IF digitizers employ two separate mixers embedded inside two independent sigma-delta modulators for I and Q paths. This chip is implemented in 0.35µm CMOS technology, achieves an equivalent image rejection ratio of 65dB at a 10MHz IF, dissipates 33mW of power, and occupies 8 mm².