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Periodic Signals MCQs

Practice Periodic Signals MCQs with four options, answers and explanations for focused Electronics & Telecommunication Engineering revision.

Question 2
Signals & SystemsPeriodic Signals

The fundamental period of x(t)=cos(20pi t) is?

  • A0.01 s
  • B0.05 s
  • C0.1 s
  • D0.2 s
Report an error
Correct Answer: C. 0.1 s
Explanation: Here omega=20pi rad/s, so f=10 Hz and T=1/f=0.1 s.
Reference: Standard signals and systems: periodic signals
Question 3
Signals & SystemsPeriodic Signals

A continuous-time sinusoidal signal is periodic when its angular frequency is?

  • ANonzero; every single continuous-time sinusoid with fixed nonzero frequency is periodic
  • BAn integer only
  • CLess than 1 rad/s only
  • DExactly pi rad/s only
Report an error
Correct Answer: A. Nonzero; every single continuous-time sinusoid with fixed nonzero frequency is periodic
Explanation: A single continuous-time sinusoid cos(omega0 t+phi) with fixed nonzero omega0 has period 2pi/|omega0|.
Reference: Standard signals and systems: periodic signals
Question 4
Signals & SystemsPeriodic Signals

A discrete-time sinusoid x[n]=cos(omega0 n) is periodic only if?

  • Aomega0/(2pi) is rational
  • Bomega0/(2pi) is irrational
  • Comega0=1 always
  • DIts amplitude is less than one
Report an error
Correct Answer: A. omega0/(2pi) is rational
Explanation: A discrete-time sinusoid is periodic if there exist integers N>0 and k such that omega0 N=2pi k, equivalently omega0/(2pi) is rational.
Reference: Standard signals and systems: periodic signals