AN ANALYSIS TO DESIGN MERGED DELAY TRANSFORMED IIR DOWN SAMPLER FILTER: AN EFFICIENT DOWN SAMPLER FILTER ARCHITECTURE

An efficient architecture of Down Sampler Filter using Merged Delay Transformed Technique in terms of cost reduction and increase throughput has been proposed. The stability analysis of Merged Delay Transformed filters, finite word length effect on Transformed filters as well as conventional filters and peak error between the output from transformed IIR filters and from conventional filters have been investigated on the basis of commercially available software and mathematical calculations. The Butterworth, Chebyshev-1, Chebyshev-2 and Elliptic filters have been considered in this paper for the sake of comparison. The simulation results show that 84.59%, 73.56% and 50.83% & 78.71%, 73.85% and 51.89% reduction in cost can be achieved with different specifications by using the proposed scheme when it is compared with conventional FIR filter, conventional IIR filter and conventional polyphase IIR filter, respectively. It has been elaborated that the stability of transformed IIR Decimation filters will not disturb as the Decimation Factor M increases. It is also shown that the transformed Elliptic filter is more stable and the transformed Chebyshev–2 filter is a marginally stable filter. The simulation results show that the peak error is in the range of 10-10 to 10-17 which increases with an increase in order of the filter. On the basis of simulation results and mathematical calculations, it is shown that the decomposition of higher order system into 1st order and 2nd order systems using parallel implementation architecture with Merged Delay Transform increases the processing rate of the filter and a reduction in the cost of implementation as well as peak error.