Signals and Systems Mid - I, September - 2011

1.The functions sin nωot, and sin mωot are always
  • Orthogonal
  • Parallel
  • Inclined
  • None
Answer: C
2.The sum of discrete exponentials with infinite amplitudes gives.
  • Complex wave
  • Periodic wave
  • Non periodic wave
  • All of the above
Answer: B
3.The Fourier transform of unit impulse function is.
  • 1
  • 0
  • S
  • 1/S
Answer: A
4.If ‘θ’ is the angle between two vectors then dot product of the two vectors contains the term.
  • cosθ
  • sinθ
  • tanθ
  • secθ
Answer: A
5.The continuous time LTI system is causal if
  • h (t) = 0 for t = 0
  • h (t) = 0 for t > 0
  • h (t) = 0 for t < 0
  • h (t) = 1 for t < 0
Answer: C
6.The Fourier transform of the exponential signal ejωt is
  • a constant.
  • a rectangular gate.
  • an impulse.
  • a series of impulses.
Answer: C
7.The auto-correlation function of a rectangular pulse of duration T is
  • a rectangular pulse of duration T.
  • a rectangular pulse of duration 2T.
  • a triangular pulse of duration T.
  • a triangular pulse of duration 2T.
Answer: D
8.The system characterized by the equation y (t) = ax (t) b is
  • Linear for any value of b.
  • linear if b > 0.
  • Linear if b < 0.
  • Non-linear.
Answer: D
9.The impulse response of a system is h(t) =ƒn at u(t). The condition for the system to be BIBO stable is
  • a is real and positive.
  • a is real and negative.
  • | a| > 1.
  • |a| <1
Answer: D
10.Region of convergence of a causal LTI system
  • Is the entire s-plane.
  • Is the right-half of s-plane.
  • Is the left-half of s-plane.
  • Does not exist.
Answer: B
11.A system is --------------- if every bounded input produces a bounded output.
Answer: stable
12.A vector is specified by ---------------------
Answer: Magnitude & Direction
13.Non-periodic signals are called the -----------------
Answer: Energy Signal
14.Periodic signals are called the ----------------------
Answer: Power Signal
15.A transmission is said to be -------- if the response of the system is exact replica of the input signal.
Answer: Distortionless
16.If the Fourier series coefficients of a signal are periodic then the signal must be -----------
Answer: Discrete-time periodic
17.The Fourier Transform of a ------------- pulse is (sinc) function
Answer: Rectangular
18.The impulse response of a cascade connection of LTI is-------------- of the individual impulse response.
Answer: Convolution
19.The signal ak u (t) is power signal if--------------
Answer: |a| = 1
20.A function x (t) is said to be even if x (t) is --------
Answer: x(-t)