There are many applications in communication systems where the sampling rat
e must be changed, Interpolators and decimators are utilized to increase or
decrease the sampling rate. Computationally efficient implementation of in
terpolators 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 l
earn and compute and can be incorporated into digital signal processing (DS
P) courses that deal with multirate filters.