Question

In Overlap save method of long sequence filtering, what is the length of the input sequence block?

(a) L+M+1

(b) L+M

(c) L+M-1

(d) None of the mentioned

I have been asked this question during an interview.

This interesting question is from Linear Filtering Methods Based on DFT in division Discrete Fourier Transform – Properties and Applications of Digital Signal Processing

Answer 1

Right option is (c) L+M-1

The explanation: In this method, each data block consists of the last M-1 data points of the previous data block followed by L new data points to form a data sequence of length N=L+M-1.