A VLSI DSP DESIGN AND IMPLEMENTATION OF COMB FILTER USING UN-FOLDING METHODOLOGY

In signal processing, a comb filter adds a delayed version of a signal to itself, causing constructive and destructive interference. Comb filters are used in a variety of signal processing applications that is Cascaded Integrator-Comb filters, Audio effects, including echo, flanging, and digital waveguide synthesis and various other applications. Comb filter when implemented has lower through-put as the sample period can not be achieved equal to the iteration bound because node computation time of comb filter is larger than the iteration bound. Hence throughput remains less. This paper present the comb filter using one of the methodology needed to design custom or semi custom VLSI circuits named as Un-Folding which increases the throughput of the comb filter. Un-Folding is a transformation technique that can be applied to a DSP program to create a new program describing more than one iteration of the original program. It can unravel hidden con-currency in digital signal processing systems described by DFGs. Therefore, unfolding has been used for the sample period reduction of the comb filter for its higher throughput