APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
FIRST SEMESTER M.TECH DEGREE EXAMINATION. DECEMBER2015

ELECTRICAL & ELECTRONICS ENGINEERING
Stream: CONTROL SYSTEMS. GUIDANCE AND NAVIGATIONAL CONTROL

OIEE6103: DIGITAL CONTROL SYSTEMS
Time: 3 hours Max marks: 60 Answer any two full questions from each part.

PART-A (Module | and II)
1 a. Analyse the sampling process in frequency domain (3)
b. Obtain the frequency response characteristics of a First-Order Hold (3)

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c.(3) Find the inverse 2 transform ச்‌ of.

(1-27)

2 a. Obtain the pulse transfer function of a digital PID controller (6)

b. For the following analog controller, find the transfer function of the (3) corresponding

digital controller using pole-zero matching method.

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‎$ + 5.5 4-6

3 3. {601 9 unity feedback system, with sampling time 7-1560, open Foop pulse (4) transfer
K(0.3679z + 0.2542)

function is G(z)= (25 0.3679)(2-1) . Determine the value of K for
stability by use of Jury's stability test. Also determine the frequency of oscillations
at the output

b. Explain Folding andAliasing (2)

c. Explain the effects of sampling period on transient response characteristics (3)

PART-B (Module ॥ and IV)

4 Consider the digital control system shown in figure. Design a digital controller 9D(z) such
that the closed loop system has a damping ratio O.S and the number of samples

per cycle of damped sinusoidal oscillation to be 8.