Practical Design Considerations for Coupled-Single-Amplifier-Biquad Active Bandpass Filters

It is commonly known that in the realization of high-order active filters, properly designed multiple-loop-feedback topologies offer far superior sensitivity performance than the approach of cascading biquadratic filter blocks.1-6 The multiple-loop-feedback structure is particularly useful in the design of bandpass filters, where reduced sensitivity design is most often needed. Compared with the cascade biquad approach, two drawbacks are usually attributed to these topologies, * Bell Laboratories, Holmdel, N.J. ®Copyright 1983, American Telephone & Telegraph Company. Copying in printed form for private use is permitted without payment of royalty provided that each reproduction is done without alteration and that the Journal reference and copyright notice are included on the first page. The title and abstract, but no other portions, of this paper may be copied or distributed royalty free by computer-based and other informationservice systems without further permission. Permission to reproduce or republish any other portion of this paper must be obtained from the Editor.