Cusat Cs 6sem Qustn Paper

(Turn Over)

BTS(C) — VI — 10 — 009 — I

B. Tech Degree VI Semester Examination, April 2010

Time : 3 Hours

CS/EC/EB/EI 605 CONTROL SYSTEMS ENGINEERING(2006 Scheme)

Maximum Marks : 100PART — A

(Answer ALL questions)

(8 x 5 = 40)I. (a) Find the inverse Laplace Transform of

s + 4 5 (i) (ii)

s(s-0(s 2 +4) s(s2 + 45+5)Distinguish between open loop systems and closed loop systems. Give one example for each.With the help of a neat diagram explain time domain specifications.State and explain Routh — Hurwitz stability criterion.Explain frequency domain specifications.

(I) State and explain Nyquist stability criterion.Explain the properties of root loci.Draw the circuit diagram of a phase-lead electrical network and derive the transfer function.

PART — B(4 x 15 = 60)

II. (a) State and explain Mason's Gain Formula. (5)(b) Write the differential equations describing the dynamics of the systems shown in the

figure and find the transfer function X2 (5)/ F(s) . ( 10)

I( I 0-150 Rn P02_

1/-6

Cl D OR

III. (a) Explain force-voltage analogy. (5)(b) Reduce the block diagram shown in the figure and find C/R. (10)

2

KGIV. The unity feed back system is characterized by an open loop T.F (s) = 4 +10).

Determine the gain K so that the system will have a damping ratio of 0.5 for thisvalue of K. Determine the peak overshoot and time for peak overshoot for unitstep input. (5)Derive the expression for unit step response of a second order under damped system. (10)

OR

V. Derive the expression for peak time. (5)Using Routh Hurwitz criterion for the unity feedback system with open loop transfer

KGFunction (s) —

s (s +1)(s +2)(s + 5)fmd the range of K for stabilityfmd the value of K for marginally stable.

(iii) Frequency of sustained oscillation when marginally stable. (10)

Sketch the bode plot of the unity feed back system whose open loop transfer function20

G find (15)is given by (s) = and the Gain margin and phase margin.s(s +2)(s +10)

ORDraw the Nyquist plot for the system whose open loop transfer function is given by

KG H(s) = (s) — . Determine the range of K for which closeds (s +2)(s +10)

loop system is stable. (15)

V Sketch the root locus for a unity feed back system with open loop transfer function isK

G (15)given by (s) —s(s2 + 8s +32)+32)

ORIX. The open loop transfer function of a unity feed back control system is given by

G (s) — s (1+ 0.2s)

Design a suitable compensator such that the system will have K =10 and phase

margin = 50°. (15)

***

BTS(C) — VI — 10 — 006 — J

B. Tech Degree VI Semester Examination, April 2010

CS/EE 602 DIGITAL SIGNAL PROCESSING(2006 Scheme)

Time : 3 Hours Maximum Marks : 100PART — A

(Answer ALL questions)(8 x 5 = 40)

I. (a) Show that for a discrete LTI system with zero initial conditions, the o/p is

y [n] = x[n]* h[n],x[n] and h [n] the i/p and impulse response respectively.

Find the stability of the system given by the impulse response

h [n] = 0.5" u [n] + 1.5" u[n] . Plot its ROC.

Show that for a periodic sequence x p [n] with DFS X,, [k], DFS of

Xp * [n] = X p * [-k] , and DFS of x p * [—n] = X p * [k] where * represents complex

conjugation.

Find the circular convolution of the two sequences x1 En1 = [1 2 1] and

x2 [n] = [1 4 2], so that it gives the same result as linear convolution. Verify that both

convolutions give the same result.Write a short note on the rectangular window method for FIR filter design. What is itsdisadvantage?What is the impulse invariant method for designing HR filters? Using this transformation,

1transform the following filter into its discrete equivalent H (s) =

(s +1)(s —1) •

(g) If the quantization step size is IV and the number of bits used for quantization m = 3,find the RMS quantization error. How will it be reduced if m is increased to 8?Calculate the percentage reduction in the RMS quantization error in the second case.Enumerate some features that distinguish DSP processors from general purpose processors.

PART — B

(a) For the impulse response below, determine if the systems are causal and stable.

h[n] = 2" u[—n]

h[n] = Sin(-7)

h[n] . [n] + Sin irn

h[n] = u[n —1].

(b) For the systems given by

(i) y[r]= Co s (x[n])

y[n]=Ax[n]+ B,

check whether the systems are linear.OR

(4 x 15 = 60)

(8)

(7)

(Turn Over)

2

Find the inverse -Z- transform of X (-Z-) = 1

2-E-4 +2-z--' +1.Determine the causal signal x [n] having the transform

X(*) -1

(1 )(1--z--1)

Show how the 8 point Radix - 2 Signal flow graph may be used to compute the

DFTs of xi [n] = [ 1 4 3 2 2 3 2 2 and x2 [n] = [ 1 4 1 2 2 3 4 2 ],simultaneously, using the signal flow graph only once. Hence , compute X1 [k]

and X2 [k] . (15)

OR(a)

What is the improvement in speed in terms of number of complex additions andmultiplications in calculating the 64 point DFT of a sequence using Direct Computationand FFT algorithm? (5)

(b) Derive the 8 point D.I.F FFT Signal Flow graph. (10)

(a) Design a Low Pass FIR filter for the following specifications :Cut off frequency = 500 HzSampling frequency = 21cHzOrder of the filter .-_ 10, and use the rectangular window for

truncating the impulse response. (8)(b) For the given FIR filter with

H (÷)= 1+ 2-z--1 +3-z72 + + 2÷-2 + , implement the filter using

least number of delay elements. Will the filter have linear phase?OR

(a) Consider the recursive relation given by

y[n] = 3y [n —1]+ y [n — 2] + 5x [n] + 2x [n —1] . Obtain itsDirect Form - 1Direct Form - 2 implementations.

(b) Obtain the linear constant coefficient difference equation of the discrete filter obtained

by discretising the analog filter H (s) = s + 1 (s +3)(s + 5).

(a) Write notes on :Limit cycle oscillations in a First Order FIR System. Hence calculatethe dead band amplitude if the quantization step size is 0.5 volt and3 bits are used for binary encoding the quantization levels.

(b) Describe using a suitable diagram an application of a DSP to image processing.OR

With a neat block diagram explain the architecture of the Texas Instruments TMS320C - 54 X fixed point processor.

(7)

(6)

(9)

(8)(7)

(15)

14*

OF SChc.

BTS(C) — V1-10 — 007 J

B. Tech Degree VI Semester Examination, April 2010CS/IT 603 OPERATING SYSTEMS

(2006 Scheme)

Time : 3 Hours Maximum Marks : 100

PART - A(Answer ALL questions)

(8 x 5 = 40)

I. a. Is busy waiting always less efficient (in terms of using processor time) than a blocking wait?Explain.What advantage is there in having different time-quantum sizes on different levels of amultilevel queuing system?What is external fragmentation? Describe a method for overcoming external fragmentation?What is Translation Look aside Buffer? Explain the steps involved in the page replacementafter a TLB miss?Compare Tree Structured Directories with Acyclic Graph Directories?Explain the steps in DMA transfer?Is it possible to have a deadlock involving only one process? Explain you answer.

h. Can a system detect that some of its processes are starving? If you answer "yes",explain how it can? If you answer "no", how the system can deal with starvationproblem?

PART - B(4 x 15 = 60)

II. Explain the concept of 'process'. With suitable diagrams explain five states of process andprocess control block (PCB/TCB).

(15)

ORIII. Consider the following set of processes, with the length of the CPU burst time given in

milliseconds

Process Burst Time Priority

PI 10 3P2 1 1P3 2 3P4 1 4P5 5 2

The processes are assumed to have arrived in the order PI, P2, P3, P4, P5 all at time 0 andsmaller priority number implies a higher priority.

Illustrate the execution of these processes using FCFS, SJF, a non preemptivepriority scheduling?What is the turnaround time of each process for each of the scheduling algorithmsdiscussed above? (15)

(Turn over)

2

Explain the concept of paging. Consider a logical address space of eight pages of1024 words each mapped on to a physical memory of 32 frames. Draw and explainpaging architecture.

ORUnder what circumstances do page faults occur. With suitable diagram describe theactions taken by the operating system when a page fault occurs.

VI. Multi programming environment demands shared directories, explain a directory structurewhich supports shared directories. Explain how this directory structure deals with

Files with Multiple absolute path names.Dangling pointers to the non existing file, after a file deletion.

ORVII. Suppose a disk drive has 5000 cylinders, numbered 0 to 4999, the Drive is currently serving

a request at cylinder 143, and the previous request was at cylinder 125. The queue ofpending requests in FIFO order is 86, 1470, 913, 1774, 1509, 1022, 1750, 130. Starting fromthe current head position, what is the total distance (in cylinders) that the disk arm moves tosatisfy all the pending request for each of the following disk scheduling algorithm(a) FCFS (b) SSTF (c) SCAN (d) C - SCAN

VIII. Consider the following snapshot of a system

AllocationABCD

MaxABCD

AvailableABCD

PO 0 0 1 2 0 0 1 2 1 5 2 0PI 1 0 0 0 1 7 5 0P2 I 3 5 4 2 3 5 6P3 0 6 3 2 0 6 5 2P4 0 0 1 4 0 6 5 6

Answer the following questions using banker's algorithm

What is the content of the matrix need?Is the system is in safe state?

c. If a request from process PI arrives for (0,4 , 2, 0), can the request be grantedimmediately.

ORIX. When a detection algorithm determines that deadlock exists, what are the possibilities to

deal with the deadlocked system? Explain in detail.

(15)

(15)

(15)

(15)

(15)

(15)

***