Group delay reduction in finite impulse response digital filters

Linear-phase finite impulse response (FIR) filters are excessively utilized in digital signal processing programs due various advantage. These advantages include that there is no distorted phase, unrestricted stability, and lower filter-coefficient insecurity. Most important shortcoming of linear-phase FIR filter is that the total group delay is (N-1)/2 where N is scope of filter. The amount becomes large to filter orders that are higher in telecommunication programs. Many algorithms have been proposed to reduce this delay and its distortion. Typically, block involution mechanism like overlap-add method (OAM) and overlap-save method (OSM) are used for a long input sequence. Yet, with respect to input, by using these techniques, the output series includes a finite group delay. In this thesis, the performance of enhanced modified overlap and save method is investigated. First, the impulse response is made causal and then it is shifted left (circular) by an amount of (N-1)/2 for N odd and N/2 for N even. Finally, the samples to be excluded from the final convolution are defined. It is expected that this results in a reduction in the causal delay and also in the group delay. Simulations are carried out by MATLAB. The performance of the method is compared with the results obtained from the OSM based filter. Keywords: Impulse Response, FIR Filter, Linear Phase FIR Filter, Group Delay.