Engineering Quantitative Aptitude English Reasoning General Knowledge Coding Others

Quiz: LCS-Frequency Domain Analysis

To View Tricks: Login Required

Number of Questions: 20

Question: 11 -

For Nyquist contour, the size of radius is _______

Options:

  1. 25

  2. 0

  3. ∞

  4. 1

    5. Answer:

    ∞
    Solution not available.

Question: 12 -

If a Nyquist plot of G (jω) H (jω) for a closed loop system passes through (-2, j0) point in GH plane, what would be the value of gain margin of the system in dB?

Options:

  1. 2.0201 dB

  2. 0 dB

  3. 6.0205 dB

  4. 4 dB

    5. Answer:

    6.0205 dB
    Solution:

    Gain Margin is calculated by taking inverse of the gain where the Nyquist plot cuts the real axis.

Question: 13 -

Consider a feedback system with gain margin of about 30. At what point does Nyquist plot crosses negative real axis?

Options:

  1. -30

  2. -0.3

  3. -3

  4. -0.03

    5. Answer:

    -0.3
    Solution:

    Gain Margin is always inverse of the point which cuts the Nyquist on the real axis.

Question: 14 -

If the system is represented by G(s) H(s) = k (s+7) / s (s +3) (s + 2), what would be its magnitude at ω = ∞?

Options:

  1. 21

  2. ∞

  3. 7/10

  4. 0

    5. Answer:

    0
    Solution:

    On calculating the magnitude of the system and putting the value of frequency one gets the magnitude as 0.

Question: 15 -

According to Nyquist stability criterion, where should be the position of all zeros of q(s) corresponding to s-plane?

Options:

  1. On right half

  2. On left half

  3. Random

  4. At the center

    5. Answer:

    On left half
    Solution not available.