Question

The transfer function of a lead controller is 1+20s/1+5s. The high frequency magnitude of the lead controller to dB is ___________

(a) 1

(b) 2

(c) 3

(d) 4

This question was posed to me at a job interview.

I need to ask this question from Cascade Compensation in Frequency Domain topic in portion Design of Control Systems

Answer 1

The correct option is (d) 4

To explain I would say: G(s) = Tp (1+Tds)/s^2

It is type-2 function.

The type-2 function has a finite steady state error for unit-parabolic input.