Analog / Mixed-Signal / RF Circuits for Complex Signal Processing

This paper describes the research history of the authors' group in the area of analog/mixed-signal circuits for complex or quadrature signal processing. Here the complex signal is composed of In-phase and Quadrature-phase signals (I, Q signals); the I-signal represents its real part while the Q-signal is its imaginary part. As complex signal processing circuits, the characteristics of the RC polyphaser filter, the complex active RC filter and the active Gm-C filter are shown and also our data weighted averaging (DWA) algorithms for complex ADCs/DACs are introduced.