An Efficient IFIR Filter Based Prototype Filter Design for Cosine Modulated Transmultiplexers

Cosine modulated filter banks and transmultiplexers are widely used because of the ease of implementation, since they have the advantage of higher obtainable attenuation in the stopband. But this leads to certain drawbacks because it would mean longer length filters and longer delays. Longer length filters would mean that that computational complexity increases. The IFIR approach to filter design is known to yield great savings in computation. In this paper an earlier approach to prototype filter design based on the Kaiser window is revisited and the same is implemented using an IFIR approach. Saving in computation will be highlighted and any deviation in performance from the previous approach will be determined. Factors governing choice of the stretch factor will be determined.