A novel mismatch cancellation and I/Q channel multiplexing scheme for quadrature bandpass ΔΣ modulators

This paper investigates and resolves in-channel/quadrature channel (I/Q) imbalances in quadrature band pass delta sigma modulators. These mismatches result in image interference and noise being aliased into the desired signal band, thus degrading the dynamic range of the modulators. A novel dynamic element match shaping scheme is proposed to cancel the aliasing of image interference, noise, and self-image. The simulation results for the proposed scheme show that the SNDR is only degraded by 1.6 dB from the ideal case (without I/Q mismatch). Meanwhile, using the I/Q channel multiplexing technique, operational amplifiers, quantizers, and digital-analog converters can be shared between I/Q channels. As a result, silicon area can be reduced with the same power consumption.