GATE 2014 EC (EC2) – Question 29

Networks, Signals and Systems · Continuous-time Signals · 1 mark · Numerical answer

For the periodic square wave shown, find the approximate ratio of power in the seventh harmonic to that in the fifth.

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Correct answer: 0.50 to 0.52

Explanation

For a50%duty-cycle symmetric square wave, odd-harmonic amplitudes are proportional to1/n, so harmonic powers scale as1/n². The ratio P7/P5=(5/7)²=25/49=**0.510204**. The common amplitude and impedance factors cancel.