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  • Question
  • If the power spectral density of stationary random process is a sine-squared function of frequency, the shape of its autocorrelation is


  • Options
  • A. If the power spectral density of stationary random process is a sine-squared function of frequency,
  • B. If the power spectral density of stationary random process is a sine-squared function of frequency,
  • C. If the power spectral density of stationary random process is a sine-squared function of frequency,
  • D. If the power spectral density of stationary random process is a sine-squared function of frequency,

  • Correct Answer
  •  

    Explanation
    Since autocorrelation function and power spectral density bears a Fourier transform relation, then since required in frequency domain will five rectangular convolutions in time domain thus it is triangular function.

    Exam Questions Papers problems


    Search Results


    • 1. If x1[n] x1(z) with ROC = R1 and x2[n] x2(z) with ROC = R2 then ROC for x1[n] + x2[n] will be __________ (where Ri ? Region of convergence and x1[n] and x2[n] are causal).

    • Options
    • A. R1 ? R2
    • B. R1 ? R2
    • C. (R1 ? R2) ? (R1)
    • D. (R1 ? R2) ? (R1)
    • Discuss
    • 2. A MOSFET has a threshold voltage of 1 V and oxide thickness of 500 x 10-8 [?r = 3.9; ?0 = 8.85 x 10-14 F/cm, q = 1.6 x 10-19 c]. The region under the gate is ion implanted for threshold voltage tailoring. The base and type of impant required to shift threshold voltage to - 1 V are __________ .

    • Options
    • A. 8.6 x 1011/cm2, p-type
    • B. 8.6 x 1011/cm2, n-type
    • C. 0.86 x 109/cm2, p-type
    • D. 1.02 x 1012/cm2, n-type
    • Discuss
    • 3. Suppose that the modulating signal is m(t) = 2cos (2pfmt) and the carrier signal is xC(t) = AC cos(2pfct), which one of the following is a conventional AM signal without over modulation?

    • Options
    • A. x(t) = Acm(t)cos(2pfct)
    • B. x(t) = Ac [1 + m(t)]cos (2pfct)
    • C.
    • D. x(t) = Accos(2pfmt)cos(2pfct) + Acsin(2pfmt)sin(2pfct)
    • Discuss
    • 4. A n-channel JFET has IDSS = 2 mA, Gate to source voltage VGS = - 2 V and trans-conductance is 0.5 mW then pinch-off voltage is __________ .

    • Options
    • A. - 2 V
    • B. 2 V
    • C. - 4 V
    • D. 4 V
    • Discuss
    • 5. What are the values of Emax and Emin displayed on the oscilloscope, when a 1 kV P-P carries is modulated to 50%?

    • Options
    • A. 2 kV, 0.5 kV
    • B. 1 kV, 0.5 kV
    • C. 0.75 kV, 0.25 kV
    • D. 0.5 kV, 1.5 kV
    • Discuss
    • 6. A transmission line has a characteristic impedance of 50 ? and a resistance of 0.1 ?/m, if the line is distortion less, the attenuation constant (in Np/m) is

    • Options
    • A. 500
    • B. 5
    • C. 0.014
    • D. 0.002
    • Discuss
    • 7. Consider a stable and causal system with impulse response h(t) and system function H(S). Suppose H(S) is rational, contains a pole at S = - 2, and does not have a zero at the origin. The location of all other poles and zero is unknown for each of the following statements. Let us determine whether statement is true or false.

      1. f[h(t) e-3t] converges
      2. h(t) has finite duration
      3. H(s) = H(- s)
      Choose correct option.

    • Options
    • A. 1 - True, 2 - False, 3 - True, 4 - False
    • B. 1 - False, 2 - False, 3 - False, 4 - True
    • C. 1 - False, 2 - False, 3 - False, 4 - False
    • D. 1 - True, 2 - can't say, 3 - True, 4 - can't say
    • Discuss
    • 8. During transmission over a communicate channel, bit errors occur independently with probability . If a block of 3 bits are transmitted, the probability of at most one bit error is equal to

    • Options
    • A.
    • B.
    • C.
    • D. none
    • Discuss
    • 9. Denominator polynomial of a transfer function of certain network is:
      s3 + s2 + 2s + 24
      Then the network is:

    • Options
    • A. stable
    • B. oscillatory
    • C. unstable
    • D. depends on numerator polynomial
    • Discuss
    • 10. In the circuit shown, in switch S is open for a long time and is closed at t = 0. The current i(t) for t ? 0+ is

    • Options
    • A. i(t) = 0.5 - 0.125e-1000t A
    • B. i(t) = 1.5 - 0.125e-1000t A
    • C. i(t) = 0.5 - 0.5e-1000t A
    • D. i(t) = 0.375e-1000t A
    • Discuss


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