Intersection filters for general decimation/Interpolation

Optimum multiple stopband FIR filters for decimation or interpolation by integer factors have been presented in the literature. In this correspondence we extend these results to the case of general decimation/interpolation by rational factors. The resulting filters are called intersection filters because their stopbands are intersections of the stopbands required in the case of integer factors. Significant improvement in stopband attenuation is found in many cases for band-limited signals.