Design of continuous time bandpass Delta Sigma modulators in CMOS

An implementation procedure for continuous time bandpass Delta Sigma modulators as a fully integrated circuit is discussed. An overview is given of the synthesis theory. A methodology for the filter design yielding practical design equations is explained. A topology for the loop filters is proposed: they are Gm-C filters. The specifications of the various building block are discussed. Considerable attention is given to non-idealities such as circuit noise, finite Q-factor and non-linearity of the transconductance amplifiers, which affect the performance of the modulator. Circuit realizations are discussed.