Efficient Implementation of FIR Filter Based Rational Sampling Rate Converters Using Constant Matrix Multiplication

It is shown that polyphase decomposed FIR filters for rational sampling rate conversion can be viewed as a matrix multiplication and several parallel delay chains. The delay chains are placed before or after the matrix multiplication depending on whether direct form or transposed direct form subfilters are used. Using recent advances in implementing constant matrix multiplication the different alternatives are discussed from a complexity point of view.