New methods for computing interpolation and decimation using polyphase decomposition

There are many applications in communication systems where the sampling rate must be changed. Interpolators and decimators are utilized to increase or decrease the sampling rate. Computationally efficient implementation of interpolators and decimators employ polyphase decomposition. In this work we present new methods for performing decimation or interpolations similar to the way numbers are multiplied on paper. Our proposed methods are easy to learn and compute and can be incorporated into digital signal processing (DSP) courses that deal with multirate filters.