Design of cascade form FIR filters with discrete valued coefficients

The authors show that by cascading two direct-form FIR filters, each with coefficients that are the sum or difference of two power-of-two terms, it is possible to achieve very small peak ripple. An iterative equalization strategy is used in the design of the cascaded filter. The success of the method depends on the initial prototype filter being used. Two equally effective methods are presented for selecting the prototype filter; each yields a final design with good roundoff noise property