# GITAM University 2007 B.E Electronics & Tele-Communication Engineering Electronics and Communication Control Systems - Question Paper

Monday, 21 January 2013 12:15Web

College of Engineering

Gandhi Institute of Technology and Management, Visakhapatnam

(Affiliated to Andhra University)

B.

**E.**(Electronics and Communications Engineering ) 2nd Year

Second Semester exams

(Autonomous Stream)

EC 227 Control Systems

**Time:**three Hours Ma

**x.**

**Marks:**60

**1.**ans ques. No. one ( Part –

**A)**and any 4 of the remaining 7 (Part – B)

**2.**All parts of a ques. must be answered in 1 place, otherwise they will not be valued.

**3.**Figures in the right hand margin indicate marks allotted.

PART – A

**1.**ans the subsequent. 10x2=20

**a)**elaborate the advantages of a closed-loop system?

**b)**Compare the terms ‘stability’ & ‘sensitivity’.

**c)**The impulse response of a system is e-0.2t. Determine the transfer function of the system.

**d)**How does the performance of an automatic control system is effected by a positive feedback signal.

**e)**State Mason’s gain formula.

**f)**describe ‘rise time’ and ‘settling time’.

g) elaborate the effects of adding poles and zeros to the transfer function?

h) State the advantages of frequency domain analysis.

**i)**What will happen if a zero is added in the forward path of a second-order system?

j) describe a series-parallel compensation.

PART – B

ans any 4 of the subsequent. If you attempt more than 4 questions, only the 1st 4 in order will be valued.

**2.**find the overall transfer function C/R from the signal flow graph shown: (10)

**3.**

**a)**Determine the mathematical model for the system shown in the figur

**e.**(5)

**b)**Derive the transfer function of field controlled dc servomotor. (5)

**4.**Measurements conducted on a servomechanism show the system response to be

C(t)= one + 0.2 e-60t – 1.2 e-10t when subjected to a unit-step input.

**a)**find the expression for the closed-loop transfer function.

**b)**Determine the undamped natural frequency and damping ratio of the system. (10)

**5.**Sketch the root locus diagram for the feedback control system having the subsequent open-loop transfer function. presume that ‘K’ will take all positive values from 0 to .

G(s) =

(10)

**6.**Draw the Bode plot of a closed-loop system which has the open-loop transfer function.

G(s)H(s) =

Determine the maximum value of ‘T’ for system to be stabl

**e.**(10)

**7.**Write short notes on the following:

**a)**Effect of derivative control on transient and steady state performance of f.B.control system. (5)

**b)**explain lead compensator. Sketch the Bode plot of a lead compensator and provide the design steps of a lead compensator. (5)

**8.**

**a)**discuss Routh-Hurwitz criterion. (4)

**b)**Investigate the stability of the system with characteristic formula.

s5+2s4+24s3+48s2 – 25s – 50 = 0

Also obtain all the roots of this formul

**a.**(6)

Earning: Approval pending. |