Test: Bode Plot - 1 - Electrical Engineering (EE) MCQ

The variation in the gain of the system has effect on the phase margin but phase plot is not affected.

Comparing with the M circle equation we have the value of M = 3.

Centre = (-0.5, 0)
Centre of N circle is (-1/2, 1/2N)
N = tanα
α = 90°.

Nichol’s chart gives information about closed loop frequency response, value of the peak magnitude of the closed loop frequency response Mp and the frequency at which Mp occurs.

A 4th order all pole system means that the system must be having no zero or s-term in numerator and s⁴ terms in denominator. One pole exhibits -20dB/decade slope, so 4 pole exhibits a slope of -80 dB /decade.

OLTF contains one zero in right half of s-plane then Close loop system is unstable for higher gain.

Nichol’s chart is useful for the detailed study and analysis of closed loop frequency response.

Transportation lag can be conveniently handled on Bode plot as well without the need to make any approximation.

Pole at 0.01 Hz gives -180° phase. Zero at 5Hz gives 90° phase therefore at 20Hz -90° phase shift is provided.

Comparing with the M circle equation we have the value of M = 3.

Centre of N circle is (-1/2, 1/2N)
N = tanα
Constant –N circles always pass through (-1, 0) and (0, 0).

Nichol’s chart is useful for the detailed study analysis of closed loop frequency response.

T. F. = Kp (1 + Tds)
There is only one zero which will give slope of +20dB/decade.

Gm (dB) = 20log⁡GM
GM = 2
As we know, GM = K (marginal)/K (desired)
K desired = 40/2 = 20.

Real part represents the damping and imaginary part damped frequency.