6th Semester Electronics and Communication Engineering (Dec-2015; Jan-2016) Question Papers

1. Ge €r^ Ec
USN
Digital Gommunication
Note: Answer FIVE full questions, selecting
at least TWO questions frr* each part.
lOEC/TE61
15/Jan.20l6
Max. Marks:100
(05 Marks)
(05 Marks)
Sixth Semester B.E. Degree Examinatio
Time: 3 hrs.
(J
o
()
L
o
0)
E
o!
3R
dU
;tr)
bo ll
coa.iI
.= c.t
d$
-O
ots
Eg
3s
O(,)
-o>!
!d=
'E6
o!
6_g
oJ
9i;3oirE
GE
!o
5*
A.=
>' (H
ooo
trc0
o=
o.B
F>
=oo-
L,)<
-: c.i
o
Z
d
o
o.
P.{RT _ A
1 a. With neat sketches explain flat top sampling. (07 Marks)
b. What is Aperture effect? Explain how it can be compensated. (05 Marks)
c. A signal g(t) = l0cos(20nt)cos(Z00nt) is sampled at the rate of 250 samples/sec.
i) Sketch spectrum of sampled signal.
ii) Specify the cutoff of ideal reconstruction filter so as to recover g(t) from gu(t).
(08 Marks)
a. Explain the block diagram of regenerative repeater. (05 Marks)
b. A PCM system uses a uniform qtantizer followed by a v bit encoder. Show that rms signal
to quantization noise ratio is approximately given Uy (t.a + Ov) db. (06 Marks)
c' With neat sketch explain companding in PCM. Also explain p-law and A-law companding.
(09 Marks)
3 a. Explain the following with neat ske&h:
i) Slope overload distortion.
ii) Granular noise. (05 Marks)
b. A delta modulator is designed to operate at five times the Nyquist rate for a signal with
3 kHz bandwidth. Determine the maximum amplitude of a 2 kHz I/P sinusoid for which
delta modulator does not have slope overload. Quantizing step size is 250 mV. (05 Marks)
c. For the binary bit stream 10011011 draw the waveforms for the following cases:
i) Polar NRZ ii) Manchester RZ iii) Gray code NRZ
d. With neat sketsh explain power spectra of discrete PAM signals.
4 a. What is ISI? Derive an expression for Nyquist pulse shaping criterion for distortionless base
band binary transmiss ion. (06 Marks)
b. What is correlative coding? Explain duobinary coding with and without precoding.
(06 Marks)
c, The binary data 011100101 are applied to the I/P of a modified duo binary system.
i) Construct modified duo binary coder O/P without precoder.
ii) Suppose that due to error in transmission, the level produced by the third digit is reduced
to zero. Construct a new receiver output. (08 Marks)
PART _ B
a. With neat block diagram, explain the DPSK transmitter and receiver. (08 Marks)
b. Obtain the expression for probability of symbol error of coherent binary FSK. (07 Marks)
c. Binary data are transmitted over a microwave link at the rate of 106 bps and the PSD of the
noise at the receiver input is 10-10.WH2. Findthe average carrier power required to maintain
an average prob. of error { <10-4 for coherent binary FSK. What is the required channel
B.W? (Take erfo (3.71) : 10-4) (05 Marks)
I of2

2. 6a.
b.
la.
b.
c.
8a.
b.
c.
lOEC/TE61
Explain the Gram Schmidt orthogonalization procedure to obtain the orthonormal basis
function for linearly independent set of signals. (12 Marks)
Three signals S,(t), Sr(t) and Sr(t)are as shown in Fig. e6 (b) Apply Gram Schmidt
procedure to obtain an orthonormal basis for the signals. Express the signals Sr(t), Sr(t)
and Sr(t) in terms of orthonormal basis functions. Also give signal constellation diagrdrn.
(oE Matks)
-lP
Show that the output SNR of a matched filter is proportional to ratio of signal energy to pSD
of input noise.
Explain the function of correlation receiver.
Determine the impulse response of matched filter.
Explain properties of PN sequence (max length sequence).
(06 Marks)
(06 Marks)
(08 Marks)
(06 Marks)
Explain the working of direct sequence spread spectrum transmitter and receiver with
BPSK. (08 Marks)
The direct sequence spread spectrum communication system has following parameters:
Data sequence bit duration Tu :4.095 ms, PN chip duration T6 : 1 ps.
+ = l0 for average probability of error less than l0-s.
No
Calculate processing gain and jamming margin. Also find jamming margin in db. (06 Marks)
2 of2

3. USN
()
o
o
I
.dl
tt-
ad
c)
0)
!
E9
Q;- ',
-v9 a
=
ra)
-ilbo"
d@
.= e.t
dr+
6)E
-oE!
Es
a=
bU
Sixth Semester B.E. Degree , Dec.20l5lJan.20l6
MicroproceSsors
Time: 3 hrs. Max. Marks:100
Note: Answer any FIVE fall questions, selecting
stleast TWO questions from each part. s e
PART-A .,.."u,'
a. Draw the internal architecture of 8086 processor and explain in brief tt*u"e*cution unit and
lOEC/TE62
(10 Marks)
(06 Marks)
(04 Marks)
b.
c.
bus interface unit.
Explain the PSW register of 8086.
List the advantages of memory segmentation of 8086.
a. Determine the physical address resulting from the following instructions:
i) Mov DL, IBP+SII
ii) Mov DI, [Bx + 100h]
iii) suB Box, Ax
iv) MOV IBP + DI + 5], AH
v) MOV AL, [5036h]
BP:7000h, SI:0350h, SS :8000t), BOX:4000h, BX:4FFFh, DS : 2000h
DI:6A00h. .,,,$,. ' (10 Marks)
b. Opcode for MOV instruction is tOOOtO. Determine the machine language code for the
following:
c. Write a program in 8087 ALP to find the areaof a circle.
E, /1 t
q
-!:
E ! r) MOV AL, BL ii) MOV AL,ll234hl t04 Marks)
&E c. What are assembler directives? Explain the significance of the following:
! a i) DW ii) EQU iii) ALIGN 16 iv) OFFSET. (06Marks)
}H
B E 3 a. Write a short note on string instructions. (10 Marks)
H : b. Using table trqnfi?ffin insiruction WAP to find equivalent seven segment code for the given
E i BCD digit,.c.#':' (06 Marks)
E Y c. Differentiate between Macros and Procedures. (04 Marks)
6v
0:
; E 4 a. Wlffid?n intemrpt? Discuss the interrupt classification in 8086 with example. (07 Marks)
E E b. ENplain the response to an interrupt in 8086. (07 Marks)
3 F c*- Write subroutines to
^=
fl*Jep
H [ r i) Set trap flag ii) Reset trap flag. (06 Marks)
o= q.'H
:t .o ed q,
F B, r-*{r ' PART _ B
;"*;: ':S a. Explain with a neat diagram the interfacing of a 4x4 keyboard to 8086. Draw the flow chart
: : aho. (Program not reqd.) (12 Marks)
; ^ b. Interface a DAC AD7523 with 8086 WAP to generate a saw tooth waveform of period 1 ms
E with V-u,: 5V. Clock frequency of 8086 : 8 MHz. (08 Marks)
f; 6 a. With a neat diagram explain the architecture of 8087 coprocessor. (10 Marks)o-
.E b. Represent the real number (13.75)d in a short real or in single precision representation.
(04 Marks)
(06 Marks)
I of2

4. rOEC/TE62
7a.
b.
8a.
b.
c.
(10 Marks)
(10 Marks)
ffi"
(10 Mdrks)i*
tQa;wYt9
ffi"PIarks)
hr-r
Draw the block diagram of PCI interface bus and explain.
Write a short note on USB.
Explain with neat dragramthe programming model of Intel80386 registers.
Explain the memory system of 80386 with diagram.
Explain Branch prediction logic and cache structure of Pentium processor.
ifift
Lc/l
*.}{
!
i
,,:, , .]|'
t,/*"
fld
ffir^d
.,
_fr##
{*
i'_--l:*
-*. "
tf
^
{ l,&w
"
J
"r' b
A.
$ Y-
if'J"'
"lq
- *^'
x" "
- &.q.d
2 of2

5. USN 108C63
..
'li
i" . ,. J"'
,,',iir..f
Sixth Semester B.E. Degree Examin .2015lJan.20l6
Microelectronics Gircuits
Time:3 hrs. Max. Marks:100
Note: Answer any FIVE full questions, selecting THREE
from PART-A and TWO fro* PART-B.
PART _ A
$ I a. Explain channel length modulation effect and derive an expression for finite output
f, resistance of a MOSFET in saturation region. ,,,, " (08 Marks)
E b. Analyze the circuit shown in Fig. l(b) to determine the voltages at all F..g and the currents
* through all branches let the nMOSFET Vt : lV and kh I = 1*q7V2. Assume l" : 0.
E
uurvuSuarrurqtwuworwuuuvrrfvlvul!r vI r v arru
^r,
t-rllu1
/
.v 1.,,..
rroou..r"r"
e
. g (08 Nlarks)
gg vpp: *ov
H= "oDr T'!-=
6v
5Tho"
EOO
.=N
.d !+
blo
BgzlomJu
E'$ 'l tEE ** *r
F I gs.$ Fig.Q2(b) (07 Marks)
5 : & n Elriaflrr cvnloin n^mmnfl rlroin omnlifier /nE tt,{d,t,6o v -.$,"L
:"tffi" c. Briefly explain common drain amplifier. (05 Marks)
Q,ff *
si 3 a. With neat circuit diagram, explain basic BJT current mirror and derive an expression for CT
g ratio of BJT current mirror for finite B. (08 Marks)
7 b. Derive an expression for 3dB frequency fn for an amplifier having 2 poles and2 zercs.
E (08 Marks)
o_
g c. Explain millers theorem. (04 Marks)
4 a. Briefly explain common source amplifier with active load. (10 Marks)
b. With neat circuit diagram, explain the MOS cascode amplifier. (10 Marks)
I of2
€E Fs;'-
1 t&=t'H,-
8E I I
Ee * h
EE ,' Fig.Q1(b)
t 8' c. Explain briefly biasing using constant current source. (04 Marks)
.dO
$: 2 a. Derive analytical expres.siCIq3for transfer characteristics of CS amplifier. (08 Marks)
: g b. Fig. Q2(b) shows u a;{''lu.t. CS MOSFET amplifier utilizing the drain to gate feedback
€ * biasing arrangemenppBtermine the small signal voltage. Gain its input resistance and the
Bg largest aflo*abffi signal. Let Vt: 1.5V, k,n
+ = 0.25mAlY2 and.va : 50V.
E I largest affowatffi signal. Let Vt : 1.5V, U;
+ = 0.25mA lY2 and.Va : 50V.
ER " L
1g " ds;F
E q *."r=;.','',,"' +%' =-|l5V
Fig.Q2(b)

6. 108C63
PART _ B
5 a. Explain the operation ofMOS differential pairwith a common mode input voltage. #^- (o7Mflm
b. Briefly explain the basic operation of BJT differential pair with neat circuit airs*[*$$..i.1
c. Explain two stage CMOS OPAMP. gi(pruarhO
ft"/
6 a. Write a note on gain desensitivity and bandwidth extension. d^v (06 Marks)
b. Draw the ideal structure and equivalent circuit of the series shunt fffi@eft amplifier and
explain. *-1q*:, (10 Marks)
c. Write a note on amplifier with a single pole response. *% ; {d (04 Marks)
dk7 A Derive an expression for the closed load gain (vo/vi) of ;[e*,chcuit shown in Fig. Q7(a).
Assume the OPAMP is ideal. r b (06 Marks)
vi
vot
i
mtation
"*p,ffim;,J11$JJ?diagram.c. With neat circuit diagram, ffiflain antilog amplifier.
'i,t. t
(08 Marks)
(06 Marks)
a. A CMOS inverter fabricated in a 0.25 pm process has Co* : 6 f F/prm2, pnCo, = 115 ltNv2,
prpCo* 30 pA, v6 * -vtp 0.4v and Vpp : 2.5v. The W/L ratio of Qn is
0.375 pm/0.}Strnn, and that for Qp is 1.125pm10.25 pm. The gate - source and gate drain
overlap gppacitances are specified to be 0.3 f F/pm of gate width. Further the effective value
of drain'uo-dy capacitances are Cam : lff and C6s, : 1 tr. The wiring capacitance
Cw
="tjlAtf'.
Find tprr, tpLu and tn. (10 Marks)
...-
b. J&ffiment F=AB+ABusingAOI. (05Marks)
c.*Explain two single input domino CMOS gate. (05 Marks)
,,,' ia;i
-4, ':
'ru r!,
,.q
*rr{<{<*
ie1 *e. o1+
2 of2

7. USN
t0EC65
(08 Marks)
(06 N{arks)
(06 Marks)
Tirne: 3 hrs.
Sixttr Semester B.E. Degree Exam
Operating Systbm
Note: Answer any FIVE full questions, selecting
utleast TWO questions from each part.
'ec"2015/Jan"2016
Max. Marks:100
2a.
b.
d
o
()
d
o.
()
()
fo
adu
_o'^^ I
trco
o Y:J
otr-o
8*
o.1J
cac
9=
.Y
dt
!=
-a()
OE
=d
c.-
?.9
6*
aoq, ti
!0
o.i
;'+
boo
.-=
go
ETVL
o
;,
63
o
o.
PART _ A
1 a. List the different tasks in an operating system. Describe the different computational
structures used in an operating system. (06 Marks)
b. With a suitable timing diagrams, explain the priority assignment rule in a multiprogramming
systems. (tl6 Marks)
c. Define the following :
i) System call
ii) Throughput
iii) Turn-around time
iv) Response time
With a suitable curve, explain the key features and concerns of diffbrent operating system
classes. (08 lVlarks)
With a neat diagram, explain the layered design of operating systems.
Explain the structure of microkernel based operating system.
Write an explanatory note on virtual rnachine operating system.
?o
b.
With a state transition diagram, explain the different states of a process and its transitions.
(06 Marks)
With a neat diagram, explain the threads used in Solaris. (06 Marks)
Discuss the problerr of race condition with a suitable example. Explain the method to
overconle this problem. (08 N{arks)
(12 iVlarks)
b. Describe the organization of sequential access and direct access fiies.
c. Write an explanatory note on FCB.
4 a. Discuss the rnethods used to achieve the memory protection with a suitable diagram.
(08 ['Iarks]
b. Describe the rnemory allocation methods for the program controlled ciata" (08 Marks)
c. Differentiate between contiguous and non-contiguous memory allocation methods.
(84ldarks)
PART _ B
a. What is demand paging? Explain the mechanisrn of address transJ,ation bi.rfflers with a neat
diagram. (08 Marks)
b. Explain the FIFO page replacement policy and LRU page replacement policy. Find the
nurnber of page faults for the following page reference string using thr;se twc policies.
Reference string : 5, 4, 3, 2, l, 4, 3, 5, 4, 3, 2, I, 5
Assume page frames : 3.
a. With a neat diagram, explain the facilities provided by the file system and IOCS layers.
(08 h4arks)
(06 Marhs)
(05 Marks)
cG,illBlL
Jtrret
l,of2

8. wr"
: T
I
7a.
b.
Expiain the long term, short term and':mediuni' term
schedulers work in case of time sharing system.
Explain the operation of preemptive scheduling policies
10EC65
schedulers. Explain how these
(10 Marks)
and its performance for the data
given below :
Process Pr Pz
p. Pq D-r5
Arrival time 0 2
a
., I
Service time J
a
J Z l J
(10 Marks)
a. Exptrain the Kernel actions to irnplement message passing using symmetric naming and
blocking sends. (06 Marks)
b. Write an explanatory note on mailboxes. (06 Marks)
c. Explain how inter-pio..r, communication can be done in IINIX. (08 Marks)
x***>r
2 of2

9. ffiUSN 10E,C64
Sixth Semester B.E. Degree Examination, Dec.2015 lJan.20l,6
Antennas and Propagation
Time: 3 hrs. Max. Marks:100
Note: Answer FIVE full questions, selecting
at least TWO questions.from each parl
PART _ A
I a. Define directivity. Obtain the relationship between directivity and beam.area to show that
smaller the beam area,larger is the directivity. (07 Marks)
b. Deflne antenna aperture. Derive the relationship between aperture and beam area. (06 Marks)
c. Show that maximum effective aperture of a short electric dipole is equal to 0.119 ).2.
(07 Marks)
.i
o
o(g
k
p-
o
d
o!
E9
d9
-.o
-^l
,=I
,= o]
l,, o
oi
3s
o9
a0i
E--o
-oG
r)
s5-
ore
o.j
9tdto
EU
o.*
ooo
iba'-E
6:5
20
EtYU
U<
-.1"..i
o
o
z
f
p.
2 a. Find the power radiated and the directivity for the following:
i) U=U*sinr0sinr$ 0<0<n 0<0<n
iD U=U_cosn0 0<0s% 0<$<2n
b. Obtain the relative field pattern for two isotropic point sources
opposite phase. spaced L u1un.
c. State and explain power theorem.
(08 Marks)
of same amplitude but
(08 Marks)
(04 Marks)
(08 Marks)
(08 Marks)
3a.
b.
c.
Derive the equation for radiation resistance of a short electric dipole.
Explain the following : i) Folded dipole, ii) Rhombic antenna.
A half wave dipole radiating in free space is driven by a current of 0.5 amperes at the
terminals. Calculate E and H field at a distance 1 km from the antenna at angles of 45o and
900. (04 Marks)
(07 Marks)
(08 Marks)
4a.
b.
c.
Obtain the radiation resistance of a small loop antenna.
Wriie shorl notes on: i) Slot antenna, (ii) Patch antenna.
Find the radiation efficiency of a I meter diameter loop of 10 mm diameter copper wire at
(i) 1MHz, (ii) 10 MHz. (05 Marks)
PART _ B
5 a. Determine the length L, H plane aperture and flare angles 0s and 0n of a pyramidal horn for
which E-plane aperture as : 10 )". The horn is fed by rectangular waveguide wittr TEro
mode. Let 6 : 0.2 X n the E-plane and 0.375 l" in the H-plane. Also find beam width and
directivity. (08 Marks)
b. Write short notes on: i) Lens antenna; ii) Log periodic antenna (08 Marks)
c' Design a Yagi-Uda six element antenna for operation at 500 MHz with a folded dipole field.
What are the lengths of (i) reflector element, (ii) driven element, (iii) four director element?
What is the spacing between reflector and driven element?
7 of2
(04 Marks)

10. 6a.
b.
10tc64
Derive an expression for resultant field intensity in the case of a space wave propagation.
(10 Marks)
Evaluate the roughness factors for the earth at 10 MHz, if o: 5, for '0' equal to (i) 30",
(ii) 45', (iii) 60". (05 Marks)
c. A transmitting antenna of 100 m height radiates 40 kW at 100 MHz uniformly in azimuth
plane. Calculate maximum LOS range and strength of the received signal at 16 m high,
receiving antenna at a distance of 10 km. At what distance would the signal strengtl-l:lkduce
to 1 mV/m? (05^Marks)
7 a. Explain the structure of ionosphere. Derive an expression for refractive index of ionospheric
c. Obtain the relationship between maximum usable frequency (MUF) and skip distance.
1ayer.
b. Define the following with respect to ionospheric propagation:
i) Critical frequency
ii) Vifiual height
Write short notes on:
a. Principle of pattern multiplication
b. Scanning array y, *.v
c. Embedded antennas !'r' ''r
d. Ground wave propagation
{.*r&*r<
. :r.
(10 Marks)
(06 Marks)
(04 Marks)
(20 Marks)
ri I
,.
r,'qu'1,.
i. ll. ..';
.,,,,",,,.,
i1
2 of2

11. USN
Sixth Semester B.E. Degree
108C665
.2015/,1an"2016
(06 Marks)
(05 Marks)
(S9 lltarks)
(08 Marks)
{05 Marks)
(&6 Marks)
(J
E
a)
d
a.)
*.)
;r)
-*Li
troo
.= c
9il
o:]
rj
OO
-o>r
H=
,()
e--
o.ro.a
-=
o=
toatE
6c
oD-
troo'-a
6=
!lo
U:
U<
*C
d)
z
(o
o
0.
Programm
Tinae: 3 hrs. l{ax. N,{arks:100
Note: Answer any FIVE full questions, selecting
stlesst TWO questions from each part"
PAR.T * A
a. What are conlments? Explain different tlpes of comments in C++ with an exarnple"
(04 Marks)
b. Distinguish between static memory allocation and dynamic memory allocation. (06 N{arks)
c. List the salient features of object oriented programming. {s6 Marksi
d. Explain the following : #elif, # if def. (04 Marks)
2 a. What are variables? Describe with an example. {s6 Marks}
b. Explain reference types and distinguish between reference tlpes and pointer types.
(08 Manks)
c. Write a C++ program to read integer numbers from keyboard until user enters zero and sum
the even nur:rbers only and display the result.
3 a" Write the O/P of followings :
i) # define square(x) x * x
void main( )
{
int i: 64lsquare (4) :
cout<<i;
l
ii) void main( )
{
t
int num, a: 15;
num:----a--a
cout<(num{<a;
)
iii) void rnain( )
I
I
int i;
for(i:0;I<5; i++)
tt
int i: 10;
print("o%d", i);
i++;
ittt
b. Write a program to find the minimum of three numbers using conditional operator.
c. Describe : break, continue and goto statements.
4 a. Describe call by value and call by reference with an example.
b. Describe inline function with an example.
c. Write a program to calculate sum of first n integers using recursion,.
(05 Marks)
I of 2

12. 10E,C665
5a.
b.
6a.
b.
PART _ B
Describe exception handling in C++ with an example.
Describe :
i) Rethrow
ii) Catch all handler.
'
Write a C++ program using class and explain public, private, object, class
Explain ftier:id function and friend class, with exarnple.
(10 Marks)
(10 Marks)
mernbers.
(10 Marks)
(10 Marks)
(10 Marks)
(10 Marks)
(08 Marks)
(12 Marks)
a. Discuss the principle of operator overioading with an example.
b. Write a program to overload both prefix and postfix increment operator.
a. Describe hase class access control with an example.
b. With a program illustrate inheritance of multiple base classes.
* * *i'.,rB.*
2 of2