Signals and Systems Mid - I, September - 2014

1.Aliasing occurs due to the following is ______________
  • fs = 2fm
  • fs < 2fm
  • fs > 2fm
  • None
Answer: B
2.Trigonometric Fourier series representation of an odd function consists of _______
  • sine terms
  • cosine terms
  • DC term
  • both a & b
Answer: A
3.A system with an input x(t) and output y(t) is described by the relation y(t) = 2t x(t). This system is ___________________
  • Linear and time-invariant
  • Linear and time varying
  • Non-linear and time-invariant
  • Non-linear and time varying
Answer: B
4.In the trigonometric Fourier series representation of a signal a0 is the __________
  • RMS value
  • peak value
  • mean square value
  • average value
Answer: D
5.The functions cos nω0t, and sin mω0t are always _________
  • Orthonormal
  • Parallel
  • Orthogonal
  • None
Answer: C
6.For a distortion-less transmission through an LTI system, the phase of H(w) is
  • Zero
  • One
  • Constant
  • Linearly dependent on w
Answer: D
7.The Nyquist rate for the signal x(t) = sin(300t) + cos(100t) is ________
  • 200 samples/sec
  • 100 samples/sec
  • 300 samples/sec
  • 600 samples/sec
Answer: C
8.Fourier transform of a unit impulse function is ___________
  • 2/jw
  • -2/jw
  • 1
  • 2π(w)
Answer: C
9.If the function x(t) has odd and half wave symmetry, then the fourier series will have only ________________
  • Odd harmonics of sine terms
  • Even harmonics of cosine terms
  • Even harmonics of sine terms
  • Odd harmonics of cosine terms
Answer: A
10.Area of f(t)(t - 10) over (- , ) is equal to ___________
  • f(0)
  • f(10)
  • f(t)
  • f(-10)
Answer: B
11.__________________ is defined to be the response of an LTI system when the input is impulse input.
Answer: Impulse response
12.__________________ of a signal can be defined as the range of positive frequencies in which most of the energy lies.
Answer: Bandwidth
13.For a distortion-less transmission, the system must have transfer function as _________________.
Answer: H(w) = K e-jwt d
14.The parseval’s theorem of Fourier Transform states that, if x(t) <-> X(W) then,  = ________________________
Answer:
15.Fourier Transform of coswo(t) is_________________________________
Answer:
16.Representation of f(t) by a set of infinite mutually orthogonal functions is called as _______________________________________
Answer: Generalized Fourier Series
17.A signal is said to be energy signal, if it satisfies the condition that _________________
Answer: 0 < E <  and P = 0
18.Let two signals f1(t) & f2(t) are orthogonal over the interval (t1, t2). Magnitude of the component of f1(t) in f2(t) is ______________________
Answer:
19.The Fourier transform of x(-t) is ______________________
Answer: X(-W)
20.The Trigonometric Fourier Series representation of a periodic signal x(t) with period To is given by __________________________________
Answer: