Question

In which of the following condition we can use the desired response hd(n)?

(a) n < M

(b) n=M

(c) n > M

(d) none of the mentioned

I got this question in homework.

My question comes from Least Squares Design Methods in chapter Digital Filters Design of Digital Signal Processing

Answer 1

The correct choice is (c) n > M

The best I can explain: Nevertheless, we can use the desired response hd(n) for n < M to construct an estimate of hd(n).