A class of digital filters for decimation and interpolation

A class of digital Finite Impulse Response (FIR) filters for decimation (sampling rate decrease) and interpolation (sampling rate increase) are presented. They require no multipliers and limited storage, thus making them an economical alternative to conventional implementations for certain applications. A digital filter in this class consists of cascaded ideal integrator stages operating at a high sampling rate and an equal number of comb stages operating at a low sampling rate. Together, a single integrator-comb pair produces a uniform FIR. The number of cascaded integrator-comb pairs is chosen to meet design requirements for stopband attenuation, passband falloff and transition width.