Lowpass & Highpass Filter Characteristics
Active filters are the building blocks of active crossovers. Filter design is an enormous subject, and it is of course quite impossible to cover even its audio aspects in a single chapter. There are many excellent and comprehensive textbooks on filters [1–3], and there would be no point in trying to create another one here. This chapter shows how to put together the blocks that make up a filter, but the design of each block to component-value level is covered in Chapter 8.
Filter design is at the root highly mathematical, and it is no accident that popular filter characteristics such as Bessel and Chebyshev are named after mathematicians, who usually did not live long enough to see their mathematics ...