The GATE Grind

GATE Networks, Signals and Systems: Continuous-time Signals – Previous Year Questions

28 GATE previous year questions on Continuous-time Signals (Networks, Signals and Systems, Electronics and Communication Engineering) with answers and explanations, from every paper.

  1. GATE 2017 EC Q18 (1 mark, Multiple choice) – A periodic signal x(t) has a trigonometric Fourier series expansion x(t) = a 0 + n=1(a n n 0 t + b n n 0 t) If x(t) = -x(-t) = -x(t - / 0), we can…
  2. GATE 2017 EC Q41 (2 marks, Multiple choice) – Let x(t) be a continuous time periodic signal with fundamental period T = 1 seconds. Let \a k\ be the complex Fourier series coefficients of x(t),…
  3. GATE 2015 EC Q27 (1 mark, Multiple choice) – The result of the convolution x(-t) * (-t - t 0) is
  4. GATE 2015 EC Q28 (1 mark, Numerical answer) – The waveform of a periodic signal x(t) is shown in the figure. [Figure: A periodic sawtooth. In each period of 3 s the signal starts at 3 and falls…
  5. GATE 2016 EC Q20 (1 mark, Numerical answer) – A continuous-time sinusoid of frequency 33 Hz is multiplied with a periodic Dirac impulse train of frequency 46 Hz. The resulting signal is passed…
  6. GATE 2016 EC Q40 (2 marks, Multiple choice) – The Laplace transform of the causal periodic square wave of period T shown in the figure below is
  7. GATE 2018 EC Q24 (1 mark, Multiple choice) – Let x(t) be a periodic function with period T=10. The Fourier series coefficients for this series are denoted by a k, that is, x(t)= k=-a kejk2Tt The…
  8. GATE 2018 EC Q64 (2 marks, Numerical answer) – A band limited low-pass signal x(t) of bandwidth 5 kHz is sampled at a sampling rate f s. The signal x(t) is reconstructed using the reconstruction…
  9. GATE 2019 EC Q16 (1 mark, Multiple choice) – For an LTI system, the Bode plot for its gain is as illustrated in the figure shown. The number of system poles N p and the number of system zeros N z…
  10. GATE 2019 EC Q31 (1 mark, Numerical answer) – Consider the signal f(t)=1+2( t)+3(23t)+4(2t+4), where t is in seconds. Its fundamental time period, in seconds, is .
  11. GATE 2020 EC Q62 (2 marks, Numerical answer) – X() is the Fourier transform of x(t) shown below. The value of - X() 2\,d (rounded off to two decimal places) is .
  12. GATE 2021 EC Q14 (1 mark, Multiple choice) – Consider a real-valued base-band signal x(t), band limited to 10 kHz. The Nyquist rate for the signal y(t)=x(t)\,x(1+ t2) is
  13. GATE 2021 EC Q49 (2 marks, Numerical answer) – The exponential Fourier series representation of a continuous-time periodic signal x(t) is defined as x(t)= k=-a kejk 0t where 0 is the fundamental…
  14. GATE 2022 EC Q15 (1 mark, Multiple choice) – The Fourier transform X(j) of the signal x(t)=t(1+t2)2 is .
  15. GATE 2022 EC Q33 (1 mark, Numerical answer) – Let x 1(t)=e-tu(t) and x 2(t)=u(t)-u(t-2), where u() denotes the unit step function. If y(t) denotes the convolution of x 1(t) and x 2(t), then ty(t)=…
  16. GATE 2023 EC Q28 (1 mark, Multiple choice) – The Fourier transform X() of x(t)=e-t2 is Note: -e-y2dy=
  17. GATE 2023 EC Q29 (1 mark, Multiple choice) – In the table shown below, match the signal type with its spectral characteristics. Signal type Spectral characteristics (i) Continuous, aperiodic (a)…
  18. GATE 2023 EC Q49 (2 marks, Multiple choice) – Let x(t)=10(10.5Wt) be passed through an LTI system having impulse response h(t)=( Wt t)210Wt. The output of the system is
  19. GATE 2024 EC Q44 (2 marks, Multiple choice) – Consider two continuous time signals x(t) and y(t) as shown below. If X(f) denotes the Fourier transform of x(t), then the Fourier transform of y(t)…
  20. GATE 2024 EC Q48 (2 marks, Multiple choice) – A continuous time signal x(t)=2(8 t+/3) is sampled at a rate of 15 Hz. The sampled signal x s(t) when passed through an LTI system with impulse…
  21. GATE 2025 EC Q18 (1 mark, Multiple choice) – Consider a continuous-time, real-valued signal f(t) whose Fourier transform F()= -f(t)(-j t)\,dt exists. Which one of the following statements is…
  22. GATE 2025 EC Q38 (2 marks, Multiple choice) – Consider a continuous-time finite-energy signal f(t) whose Fourier transform vanishes outside the frequency interval [- c, c], where c is in rad/sec.…
  23. GATE 2025 EC Q55 (2 marks, Multiple select) – Let f(t) be a periodic signal with fundamental period T 0>0. Consider the signal y(t)=f( t), where >1. The Fourier series expansions of f(t) and y(t)…
  24. GATE 2026 EC Q15 (1 mark, Multiple choice) – Two analog signals x 1(t) and x 2(t) (t in second), are sampled at a rate F s = 40 Hz, where x 1(t)=(20 t),\, t0, and x 2(t)=(100 t),\, t0. The first…
  25. GATE 2026 EC Q37 (2 marks, Multiple choice) – The continuous time signal x(t) is real, periodic with period T and satisfies the Dirichlet conditions. The Fourier series representation of x(t)= -a…
  26. GATE 2026 EC Q43 (2 marks, Multiple choice) – Consider a real signal x(t), -<t<, such that x(t)=0 for t<0, x(t)=2 for 0 t<1 and x(t)=0 for t1. Let E[x(t)]= -[x(t)]2dt. Which of the following…
  27. GATE 2026 EC Q46 (2 marks, Multiple choice) – Consider a real baseband signal x(t)=e-2t, for t (in seconds) 0. If 99% of energy of x(t) lies within B Hz, then which of the following options is…
  28. GATE 2026 EC Q58 (2 marks, Multiple select) – Let x 1(t)=(2 nt) and x 2(t)=2(4 nt) represent two sinusoids for a positive integer n and -<t<. Which of the following statements about x 1(t) and x…