Design of Modified Three Stage Sharpened CIC Filter for Decimation

This paper presents the design of Sharpened three stage CIC filter for decimation. The proposed decimation filter has Cascaded-Integrator Comb filter as first stage, Sharpened Cascaded-Integrator Comb filter as second and third stage. The CIC filter at first stage operates at input sampling rate, sharpened second stage operates at lower rate as compared to first stage and sharpened third stage operates at lower rate as compared to first as well as second stage. The sharpened second and third stage leads to improvement in pass-band droop and better stop-band alias rejection. Further the reduction of sampling rate at each stage provides many additional benefits like better power efficiency, reduced hardware requirements, reduced cost and better speed. The proposed filter is designed and simulated in MATLAB-Simulink environment. The simulation results and their comparison shows that the proposed decimation filter has improved pass-band droop and better stop-band alias rejection than the existing structures.