Generalized approach to sampling rate alteration in wave digital filters

Generalized arrangements (wave-flow diagrams) for sampling rate alteration in wave digital filters (WDFs) are proposed and analyzed. By this new approach, the number of degrees of freedom of the resulting so-called multirate WDF is not reduced in relation to that of the reference circuit. Advantages of the earlier multirate WDF's, such as improved loss performake for a given filter structure, increased dynamic range, and low passband sensitivity for coefficients, are preserved. Necessary and sufficient realiiability conditions for the generalized multirate WDF's are also presented. It is assumed that the reference filter is lossless, reciprocal, and rational in its complex frequency 4. An example of a fifth-order WDF for sampling rate increase is given.