6th Semeste Electronics and Communication Engineering (June-2016) Question Papers

1. 6* gen Pc'
PART A
I a. Explain sampling theorem of low pass signals and derive the interpolation formuia"
(08 Marks)
b. A low pass signal x(t) has spectrum X(f) given by,
(t
x(r)=]t-#' lrl<2oo
| 0 Elsewherc
.Sketch the specti'um Xa(| for l{ < 2A0 Hz if x(t) is ideally sampled at f, : 300 Hz" (05 N{arks)
c. d band pass signal g(t) with a specirum shown in Fig.Ql(c) is idealtry sampled. Si<etch the
spectrum of sampled signal at f, : 25 Hz and f, : 45 Hz. Indicate if and how the signal can
be recovered.
Fig.Q i (c) (86 Marks)
Derive the expression for signal to quantization noise ratio (SNR) and show that for uniform
quantization, each bit in the codeword of a PCM contributes 6 dB to SNR. (08 Marksi
For a binary PCM signal, determine L if the compression parameter pr : 100 and the
minimum ISNR]6 dB : 45 dB. Deterrnine the ISNR]g dB wittri this value of L" (06 Marks)
With a neat block diagram and waveform, explain time division multiplexing. (05 Marks)
Explain the principies of delta modulator. With relevant flgure and rnathematical
expressions, explain the functioning of DM transmitter and recetver. (08 Marks)
b. For a binary sequence i 1100011010i draw the digital format waveforms corresponding to:
i) Bipolar NRZ waveform and ii) 8-ary signaling waveform. (06 Marks)
c. Derive an expression for power spectral density of bipolar l{RZ format and plot the sarne
with respect to &equency. (05 Nlarks)
4 a. What is correlative coding? Explain duo binary coding with and without precoding.
(08 Marks)
b. The binary data 011100101 are applied to the input of a rnodified duo binary system:
i) Construct the modified duo binary coder output and corresponding receiirer output
without a precoder.
i, Suppose that due to error in transmission, the level produced by the tirird digit is
reduced ta zero. Construct a new receiver output. {07 Marks)
c. With a neat block diagram, explain the concept of adaptive equalization. (05 Nlarks)
USN
Time: 3 hrs.
Digital Gommunication
Note: Answer FIVE fwll questions, selecting
at least TWO questions.from euch purt"
Max. Marks:100
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PART _ B
With neat block diagram, explain DPSK transmitter and receiver. Illustrate the generation of
differentially encoded sequence for the binary input sequence 00100110011110. (12 Marks)
A binary data is transmitted over an AWGN channel using binary phase shift keying at the
rate of 1 Mbps. it is desired to have average probability of error P. s i0-4. Noise power
spectral density is Noz : 19-12 WlHz. Determine the average carrier power required at the
receiver input, if the detector is of coherent type. Take erfc(3.5) : 0.00025. (08 Marks)
6 a. Write a note on Gram-Schmidt orthogonalizatronprocedure.
b" Consrder the signal sr(t), s2(t), s3(t) and s4(t) as given below in Fig.Q6(b).
s3c )
sr-Ja "L o 1T3 rbo
(08 Marks)
(12 Marks)
(08 Marks)
is given by
(tr2 Marks)
(08 Marks)
(06 Marks)
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Fig.Q6(b)
Find an ofihonormatr basis for these
procedure.
set of signals using Gram-Schmidt orthogonahzation
Draw and explain the block diagram of correlation receiver.
Show that the probability of bit error of a matched filter receiver
p =1errc tr'- ? 1i Nlo
Wrat is spread spectrum technique? F{ow are they classified?
Explain properties of PN sequence.
A slow FF{/MFSK system has the following parameters:
The number of bits/MFSK symbol :4
The number of MFSK symbols per hop : 6
Calculate processing gain of the system. (06 Marks)
8a.
b.
C.
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3. USI,{ lOEC/TE52
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diagram along with
(14 Marks)
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(04 Marks)
Sixth Semester B"E. Degree Examinatiom, June/July 2015
Microprocessors
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2a.
Note: Ayeswer srny F{VE fwll qaaestiows, selecting
atleast TW{} Ernestians from e&ch pert.
PARE A
With a neat diagram explain the internal architecture of 8086"
Explain aboilt segment registers and its advantages.
Explain about instruction execution time dependency paramrters.
Explain the following instruction function with an example:
(i) LooP (ii) rMUr. (iii) XLAr (iv) AAvi
b. What is assembler directive? Explain the following assembler directives:
(r) ASSUME (ii) PUBLIC (iiD ALIGN
c. Write an ALP to perform GCD of two l6-bit integers and comments.
a. Write an ALP to perforrn reversing string along witir flow chart.
b. List out two differences between MACRO and PROCEDLIRE,.
c. List and briefly explain String instruction"
EART__ E
5 a. What is interfacing? Explain about m x n rnatrix keyboard interface
progtafil end flow chart.
b. Briefly'explain about 8255 control word format.
7 a. Explain rnaxirnum mode operation of 8086 with relevant block diagrarn.
b. Write a short note on FCI and USB.
8 a. Write the salient features of 80486.
b. Briefly explain about 80386 special registers.
c. Write a note on Pentium processor..
a. What is interrupt? Explain about dedicated interrupts with respect to 8085. (08 Marks)
b. Briefly explain about hardware and software interrupt apptrications. (06 Marks)
c. What are the steps involve during the interrupt response. (05 Marks)
6 a,, Fxplain about control register of 8087. (06 Marks)
b: Explain about various data types with respect to 8087. (CId Marks)
c. What is co-processor? Why it is calied so? Give the signifncance of, 8087 NDP" (sB Marks)

4. USN 10EC63
Sixth Semester B.E. Degree Examination) , 2016
Max. Marks:100
Microelectronic Gircuits
Time: 3 hrs.
Note: Answer FIVE full questions, selecting
any Threefrom Purt-A and Twofrorn Psrt-&.
PART _ A
I a. Derive the expression of io - Vos relationship for triode and saturation region of a NMOS
transistor. (10 Marks)
b. For the MOSFET with I =
8l*
, calculate the values of V6s and Vos(rnin) needed to
L 0.8 prm
operate the transistor in the saturation region with a dc current Io : 100. Assume
K;:194 $NV'and V1 : 0.7 V. (05 Marks)
c. Write the expression for the relationship between Vse and Vt. Mention the effect of Vse on
the channel. t05 Marks)
6a.
b.
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2 a. What are the benefits of short channel MOSFETs?
b. Explain the operation of a MOSFET current mirror.
c. Draw the circuit of a MOS current steering circuit and explain it.
a. Explain CMOS implementation of the common souree amplifier and also
characteristic of the active load and transfer characteristic.
b. Consider a common gate amplifier specified as follows :
W 7.2tm
L 0.36prm ' n
(05 Marks)
(06 Marks)
(08 Marks)
draw its i-v
(10 Marks)
Rs: 10 Kf),
Gi and ft.
RL : 100 Kf) , Cs, :20 ff, Cga: 5 ff and Cr-: 0. Find Avo, Rin, Ro.,t, Gv, Gi,,
(10 Marks)
4 a. What is cascade amplifier? Mention the basic idea behind it. (04 Marks)
b. Derive the expressionof voltage gain and open circuit voltage gain of a lC-source follower.
Draw its small signal equivalent circuit model. (08 Marks)
c. Explain the operation of a MOS differential pair with common-mo<Ie input voltage.
(08 Marks)
a. Explain the operation of a two-stage CMOS op-amp configuration. Mention its features.
(10 Marks)
b. Illustrate the method of differential to single-ended conversion. (07 i{arks)
c. What are the factors contribute to the dc offset voltage of the MOS differential pair?
(03 Marks)
PART _ B
Discuss the properties of negative feedback in details. (08 Marks)
Explain the relationship between stability and pole location of an amplifier with effects.
(05 Marks)
Draw the block diagram, represeniation of a serie s-shunt feedback amplifier and derive the
expression of input resistance with feedback. (06 Marks)
I of 2

5. la.
b.
c
8a.
10E,C63
Design a non-inverting amplifier with a gain of 2. At the maximum output voltage of
l0 V and the current in the voltage divider is to be l0 prA. (05 Marks)
With a mathematicatr analysis and circuits, explain the temperature effects in Logarithmic
amplifier are to be minimized. (09 Marks)
Draw the sample and hold circuit using op-amp and explain it. (05 Marks)
Define the following parameters of a logic circuit family and write the expressions :
i) Propagation delay.
ii) Robustness
iii) Delay-power product.
iv) Dynarnic power dissipation.
b. Implement:
i) p'= 49 -.l.6p using the AND-OR-INVERT gate logic.
ii) F = G + BXC + DJ using the OR-AND-INVERT gate logic.
(08 Marks)
(12 Marks)
*****
2 of2

6. USN
, 108C64
2016
Max. Marks:100
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Sixth Semester B.E. Degree Examination, June/July
Antennas and Propagation
Note: Answer FIVE full questions, selecting
at least TWO questions from each part.
PART _ A
7 a. Explain the following terms as related to antenna systems:
i) Beam area
iv) Effective aperture
b. Find the directivity of the
o<0<n.
ii) Directivity iii) Power gain
Time: 3 hrs.
4a.
b.
c.
c. Anantennahasafieldpatterngivenby E(e)=coS0cos20 for 0<0<90". Findhalf power
beam width (HPBW) and beam width between first nulls (BWFN). (85 Marks)
2 a. Derive an expression for array factor and relative field of linear array of 'n' isotropic point
sources of equal magnitude and spacing. (08 Marks)
b. Complete the field patterns and find BWFN and HPBW for an array of 4 point sources
spaced ),/6 distance apart. They have a phase difference of nl3 between adjacent elements.
c. Explain the principle of pattern multiplication with an example.
(06 Marks)
(06 Marks)
(07 Marks)
v) Radiation resistance (10 Marks)
power pattern given by U='U,nsin'Osin'0; 0s0<n;
(05 Marks)
(06 Marks)
(07 Marks)
(07 Marks)
(06 Marks)
3 a. Derive the far field components of short dipole.
b. For a short dipole of ),/15 long and loss resistance of 1Q. Find:
i) Efficiency
ii) Radiation resistance
iii) Effective aperture
c. Write short notes on:
D V-antennas
ii) Folded dipole antennas
iiD Rhombic antenna
Derive the far field expressions for small loop antenna.
Explain pritch or microstrip antennas with necessary sketch.
With relevant sketches, explain the principle of Babinet's principle for complementary linear
antennas. (07 Marks)
PART _ B
a. Explain the practical design considerations for the axial mode helical antennas. (10 Marks)
b. Write short notes on:
i) Yagi-Uda antenna
ii) Corner reflector antenna
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(10 Marks)

7. 108C54
Explain the constructional details of Sleeve antenna and Turnstile antenna. (08 Marks)
b. Write short notes on:
. i) Embedded antennas
ir) Ultra wideband antennas
iii) Flasma antennas (12 Marks)
7 a. Derive an expression for wave tilt of surface wave. (08 Marks)
b. Explain duct propagation in detail" "(Q6 Marks)
c. Estimate the wave tilt in degrees of the surface wave over an earth of 5, millimhos
conductivity and relative permittivity of 10 at 1 MHz. (06 Marks)
Ba.
b"
Derive an expression for refractive index of an ionospheric propagation. (06 Marks)
A high frequency link is established for a range of 2000 km. If the reflection region of
ionosphere is at a treight of 200 km and has a critical frequoncy of 6 MHz, calculate
maximum usable frequency (MUF). (06 Marks)
Define the following terms related to ionospheric propagation:
D MUF
i0 Critical frequency
iii) Vifiual height
iv) Skip distance
C.
(08 Marks)
2 of2

8. USN 108C65
Sixth Semester B.E. Degree Examination, June/July 2016
Operating Systems
Tirne: 3 hrs. Max. Marks:100
Note: Answer FIYEfull questions, selecting
at least TWO questions from euch part.
PART _ A
a. Define OS. What are the common tasks perforrned by an operating system? (08 Marks)
b. Explain briefly, the different classes of operating system, with primary concern and key
concepts. (08 Marks)
c. What are the operations performed by Kernel when an intenupt occurs? (s4 Marks)
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b.
4a.
b.
c.
5a.
b.
6a.
Explain : (i) Monolithic OS and (ii) Microkemal OS
Specifying advantages and dis-advantages in each case.
Define the following with respect to an operating system:
(r) Policies and mechanisms. (ii) Portability and Extensibility
Briefly explain the concept of VMOS, with an example.
Briefly explain four kinds of process interaction.
With state transition diagram, explain the state transition for a process.
What are the advantages of threads? Explain briefly Kernel-level and
specifying advantages and disadvantages.
Explain Kernel memory allocator methods.
What are the key features in static and dynamic memory allocation?
Explain briefly memory compaction with an example.
PART - B
With reference to virtual memory, explain the following:
(i) Demand paging (ii) Page replacernent policies.
Explain UNIX virtual memory.
Explain file operations performed by processes.
(08 Marks)
(08 Marks)
(04 Marks)
(06 Marks)
(06 Marks)
user-level threads,
(08 Marks)
(10 Marks)
(06 Marks)
(04 Marks)
c.
7a.
What are the facilities provided by file-system and IOCS? Write the layered architecture of
the systam. (06 Marks)
Explain (i) Sequential flle organization (ii) Direct file access organizatian. (05 Marks)
Define Turn-around-time. Compare average Turn-Around-Time, for
for FCFS and SRN scheduliano 5Ki scneoutm
Process D,rl Pz P: P+ P.
Arrival time 0 2
a
J 5 9
Service time 3
1
-) 2 5 -)
(10 Marks)
(10 Marks)
(08 Marks)
the following set of
(08 Marks)
b. Briefly explain process scheduling methods for real time applications.
c. Explain briefly, scheduling in UNIX.
8 a. How interprocess communication is achieved through mail-box? What are
b. Explain the following:
(i) Synchronous and asynchronous message passing.
(ii) Data - access synchronization.
(iii) Control synchronization.
(06 Marks)
(06 Marks)
its advantages?
(08 Marks)
(12 Marks)

9. USN 108C665
Max. Marks:10Or
(10 Marks)
(04 Marks)
Sixth Semester B.E. Degree Examination, June/July 2016
Programming in G++
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Time:3 hrs.
c. Distinguish between L-value and R-value. Give example for each.
quadratic equation ax2 + bx + c: 0 use switch.
c. With flowchart, explain i) For ii) While.
b.
7a.
b.
8a.
b.
Note: Answer FIVE full questions, selecting
ut least TWO questions from each parl
PART _ A
Explain with example preprocessor directive available in C++. (08 Marks)
Explain dynamic memory allocation. What is the difference between static and dynamic
memory allocation. (07 Marks)
Explain object-oriented design and object based design. Give example. (05 Marks)
What is a literal constant? Explain with example. (06 Marks)
What are the difference between a reference and a pointer? Give advantages of pointer.
(08 Marks)
(06 Marks)
c.
3 a. Discuss the following with example: i) Unary operators; ii) The Bitwise operator.(06 Marks)
b. Explain the switch statement with syntax. Write a program in C++ to find the roots of
4 a. Explain cail by value and call by reference parameter method with an example of each.
(08 Marks)
b. What is an inline function? Explain with example. (04 Marks)
c. Write a program to find the maximum number in an array use max ( ) function to irnplement.
(08 N{arks)
5a.Whatisanexceptionhandling,*ffi,fferenttypesofexceptionandexplainthe
exception handling mechanism. (10 Marks)
b. Explain the different throwing mechanism. Write a program to realize the expression and
handle the exception R = (10 Marks)
y-x
6 a, With simple C** program, using class, explain the term, object, private, public, constructor
and destructor. (10 Marks)
Write a C++ program to define a class 'stack' including member function push ( ) and
pop ( ) and appropriate data members to perform the stack operation. (10 Marks)
What is operator overloading? Write a C++ program to add two complex members by
overloading the operator *. (10 Marks)
What are new and delete operator? Explain overloaded operator new and delete with
example. (10 Marks)
What is inheritance? Discuss the different types of inheritance. (10 Marks)
Explain what is the relationship between class, base class, derived class and protected
members, with the help of examples. (10 Marks)
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