Question

In Overlap save method of long sequence filtering, how many zeros are appended to the impulse response of the FIR filter?

(a) L+M

(b) L

(c) L+1

(d) L-1

I got this question in my homework.

The query is from Linear Filtering Methods Based on DFT in portion Discrete Fourier Transform – Properties and Applications of Digital Signal Processing

Answer 1

Right option is (d) L-1

The best I can explain: The impulse of the FIR filter is increased in length by appending L-1 zeros and an N-point DFT of the sequence is computed once and stored.