GATE 2021 IN – Question 54
The shown input signal passes through the filter with the shown taps. The number of nonzero output samples is ______.
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Correct answer: 10 to 10
Explanation
The taps −1,2,−1 form a discrete second difference. It is zero in every constant plateau of the input. At each jump between levels (0→1,1→2,2→3,3→1,1→0), the difference produces two adjacent nonzero samples with opposite signs. The plateaus are sufficiently long to avoid overlap, so there are 5·2=**10** nonzero samples.