Synthesis of a low-sensitivity multiloop feedback active RC filter

A general, low-sensitivity multiloop feedback configuration for realizing higher order transfer functions is presented. A synthesis procedure, which incorporates the desirable building block approach of cascade design, is described. In particular, the paper is concerned with the realization of higher order narrow-band bandpass (BP) functions where either biquad or Tarmy-Ghausi (TG) networks are used as active blocks. A sensitivity expression, dependent explicitly on the individual active block Q's and loop gains, is derived and minimized. The results demonstrate the low-sensitivity performance of the structure which, for some designs is superior to that of the "leapfrog" (LF) configuration, especially over a wide-band of frequencies.