Fast Design of IIR Digital Filters With a General Chebyshev Characteristic

In this brief, a fast design technique based on a multiband mapping relation is discussed for infinite-impulse-response digital filters with a general Chebyshev characteristic, which is suitable for single- and multiband operations. Each bandwidth and the ripple in it can be accurately controlled. Without increasing the order of the filters, the out-of-band performance of the filters can be easily adjusted by appropriately placing transmission zeros wherever they are desired. In addition, complex transmission zeros can also be introduced to improve the group delay to some extent. The proposed technique is analytical and easy to implement.