logo

CuriousTab

CuriousTab

Discussion

Home ‣ Electronics and Communication Engineering ‣ Signals and Systems See What Others Are Saying!
  • Question

  • Which one is a linear system?


  • Options
  • A. y[n] = x[n] x x[n - 1]
  • B. y[n] = x[n] + x[n - 10]
  • C. y[n] = x2[n]
  • D. (a) and (c)

  • Correct Answer
  • y[n] = x[n] + x[n - 10] 

    Explanation
    For linearity

    y1[n] = x1[n] + x2[n - 10] ...(1)

    y2 = x2[n] + x2[n - 10] ...(2)

    y1[n] = x1[n] + x2[n] + x2[n - 10] + x2[n - 10] ...(3)

    Now find y1[n] + y2[n]

    Corresponding to x1[n] + x2[n]

    It is same as equation (3) hence linear.

    But in part (c) y[n] = x2[n]

    ? y1[n] = x21[n], y2[n] = x22[n]? y1[n] + y2[n] = x22[n]...3

    But y1[n] + y2[n]

    Corresponing x1[n] + x2[n] is y1[n] + y2[n] = {x1[n] + x2[n]}2

    = x12[n] + x22[n] + 2x1[n] x2[n]....4

    Equations (3) and (4) are not same hence not linear.

    More questions

    • 1. The output frequency of a cycloconverter can be changed by changing the firing angle.

    • Options
    • A. True
    • B. False
      • Discuss
    • 2. Most of the memory chips in static RAM

    • Options
    • A. do not require any supply
    • B. need 2 V supply
    • C. need 5 V supply
    • D. need 12 V supply
      • Discuss
    • 3. In crystalline solids, atoms are stacked in a regular manner.

    • Options
    • A. True
    • B. False
      • Discuss
    • 4. The classes of solid dielectrics are

    • Options
    • A. A, B, C, D, E, F, H
    • B. A E B F H C D
    • C. Y A E B F H C
    • D. A E B F H C
      • Discuss
    • 5. The unit for mmf is

    • Options
    • A. A
    • B. Wb
    • C. T
    • D. V
      • Discuss
    • 6. In a single phase full wave regulator, the firing angles in the positive and negative half cycles are generally

    • Options
    • A. equal
    • B. different
    • C. equal or different
    • D. different but sometimes equal
      • Discuss
    • 7. The real part of complex dielectric constant and tan? for a dielectric are 2.1 and 5 x 10-4 at 100 Hz respectively. The imaginary part of dielectric constant at 100 Hz is

    • Options
    • A. 1.05 x 10-3
    • B. 2.1 x 10-3
    • C. 5 x 10-3
    • D. 1.05 x 10-2
      • Discuss
    • 8. The units for ?r are

    • Options
    • A. Farads
    • B. Farads/m
    • C.
    • D. no units
      • Discuss
    • 9. Tesla is a unit of

    • Options
    • A. flux
    • B. field strength
    • C. flux density
    • D. MMF
      • Discuss
    • 10. In a receiver, which of the following device has IF input but RF output?

    • Options
    • A. Demodulator
    • B. Loudspeaker
    • C. Audio amplifier
    • D. Frequency changer
      • Discuss

    Comments

    There are no comments.
Enter a new Comment




Aptitude

Engineering

Programming

Reasoning

Links

Copyright ©CuriousTab. All rights reserved.