Multiple-loop-feedback switched-capacitor filters using approximating biquads (original) (raw)

A method is suggested for the design of multiple-loop-feedback (MLF) switched-capacitor (SC) bandpass filters using biquads the frequency response of which is not 'exact' bandpass. From the point of view of chip area, the employment of such biquads leads to economical MLF filters which these circuits require for their construction as fully integrated circuits. The method is extended to the design of MLF lowpass SC filters, for which use is suggested of biquads realising functions other than the usual lowpass functions. This means that the feedback signal entering the BP 00