The Biquad: Part II--A multipurpose active filtering system

While the electrical performance of the Biquad insures that active filter designs using this structure will be useful over a wide range of conditions, the Biquad topology offers unique flexibility compared to other active realizations. We now present the concept of the multipurpose active filter. For example, switchable and adaptive filters are easily realized and different functions (e.g., bandpass and band-reject) are obtainable simultaneously from the same structure.