Efficient digital-signal-processor realization of multirate filter banks using wave digital filters

Lossless multirate filter banks (FBs) can be used in a very efficient way for many signal processing tasks. They offer a high degree of freedom concerning the specification of the transfer characteristics. The implementation of such FBs is considered. The properties of real and complex FBs are discussed, and a solution for avoiding undetermined bands is given. Wave digital filters (WDFs), which are derived from classical filters, can be used with a high degree of performance for the realization of these FBs. By using simple modifications of the filters the realization of the WDF-FBs by commercial digital signal processors (DSPs) can be done very efficiently. Various applications are presented, e.g., a single DSP coding system for high-quality audio signals and a new approach for a complex FB for spectrum analysis