Question

If {x(n)} is the signal to be analyzed, limiting the duration of the sequence to L samples, in the interval 0≤ n≤ L-1, is equivalent to multiplying {x(n)} by?

(a) Kaiser window

(b) Hamming window

(c) Hanning window

(d) Rectangular window

The question was asked in an online quiz.

This key question is from Frequency Analysis of Signals Using DFT topic in section Discrete Fourier Transform – Properties and Applications of Digital Signal Processing

Answer 1

Correct answer is (d) Rectangular window

Easiest explanation: The equation of the rectangular window w(n) is given as

w(n)=1, 0≤ n≤ L-1

=0, otherwise

Thus, we can limit the duration of the signal x(n) to L samples by multiplying it with a rectangular window of length L.