Perfect reconstruction filter banks with rational sampling rate changes

The authors present a general, direct method for designing perfect reconstruction filter banks with rational sampling rate changes. Such filter banks have N branches, each one having a sampling factor of p/sub i//q/sub i/ and their sum equal to one. A design example showing the advantage of using the direct over the indirect method is given. Due to recent results pointing to the relationship between filter banks and wavelet theory, the regularity question is addressed as well, and a regular filter is shown for a dilation factor of 3/2.