Production of complex active filters
Active filters - Synthesis and fabrication

For low-order filters (up to 8, for example), with a bandwidth B that's not too small (order of magnitude: B > 20%), synthesis by simple cascading of biquadratic cells is suitable. In this case, the Q coefficients of the cells remain low or moderate (Q < 10 to 15, for example), and sensitivities remain acceptable. The design is very simple, and the independence of the individual cells facilitates adjustment.

Three precautions should be taken in practice:

• ensure that the cascading order preserves the filter's dynamic range: high leading Q for weak signals...