Con. 6051-10.

GE1£1 ((.2) NO\! J D~c 't6.5~ b - c c. N

(REVISED COURSE)

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GT -8898

N.S. :>"exv?- :vT1.:..---

(1) Question No.1 is compulsory.(2) Attemptany four questions out of remaining six que(3) Figures to the right indicate full marks.

( 3 Hours) [ Total Marks: 100

1; (a)

. (b)

(c)

(d)

Explain Classless Interdomain routing.ExplainALOHAand Slotted ALOHA.Explain the working of selective repeat ARQ.What is Distance Vector Routing?

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2. (a) Draw the various Network Topologies and explain with advantages ana 10,disadvantages of each.

(b) Explain sliding window flow control with the help of a neat diagram. 10

3. (a) Explainthe ISO-OSInetwork model in detail with the help of a neat diagrams. 10, '

(b) Discuss the various Scheduling methods used in medium access control. 10

4. (a) Discuss the various modes, configurations and fra,me formats in HDLC. 10(b) Explain the various Networking and Internetworking devices in detail with 10. I

the help of neat sketches.

-5. (a) Compare Circuit Switching, Packet Switching and Message Switching. 10(b) Drawthe IP packet format and explain the functionof each field in detail. 10

6. (a) Compare TCP and UDP.(b) Explain ARP and HARP in detail.

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7. Write short notes on (any three) :-(a) ClassfullP Addresses(b) Bellman Ford Algorithm.(c) IEEE Project 802(d) Delay Analysis.

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\\5 Oeh I 0 Scan 63

Con. 6326-10. (REVISED COURSE)

(3 Hours) :' 100!..

N.S. : (l)Question No.1 is compulsory. - ._. - -_.~

(2)Attempt any four questions from remaining six questions.(3)Assume suitable data if neces~~EYand state it cle8:!lY.

1. (a) Explain speech production mechanism.

(b) Write a note on spectrogram.

(c) Define short-time autocorrelation function. Explain all the stepsin computation of short-time autocorrelation function.

(d) State and explain in brief applications of linear predictive analysisto speech processing.

2. (a) If the sequences x(n) and w(n) have normal Fourier transformsX(ejW) and W(ejW), then prove that for fixed n the short-timeFourier transform

00

Xn(ejW) = L x(m)w(n - m)e-jwmm=-oo

can be put in the form

Xn(ejW) = ~ j 7r W(ejO)ejOTl.X(~(w+o)) dB27r -7r

(Hint: use fourier transform properties)

(b) Consider a discrete time signal x(n). Define autocorrelation func-tion.State properties of autocorrelation function. If x(n) is peri-odic define autocorrelation function. Will it be periodic? Explain.

3. (a) Explain basic principles of linear predictive analysis.

(b) Draw and explain general discrete-time model for speech production.

4. (a) Explain in detail pitch period estimation of speech signal x(n) us-ing autocorrelation function.

(b) A speech signal is sampled at a r'ate of 20000 samples/see (20KHz). A segment of length 1024 samples is' selected and the 1024point DFT is computed.

i. What is the time duration of the segment of speech?

ii. What is the frequency resolution ( spacing in Hz) between theDFT values?

iii. How do your answers to above parts change if we compute the1024 point DFT of 512 samples of the speech signal. (The 512samples would be augmented with 512 zero samples before thetransform was computed.)

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[ TURN OVER

WS Oct- 10 Scan 64

Con. 6326-GT-8902-10. 2

5. (a) Draw the block diagram of speaker verification system. Explainsignal processing aspects of the speaker verification system.

(b) Draw the block diagram of linear predictive speech synthesizer.Explain how speech is synthesized using this method. What arethe main advantages of this method?

6. (a) A newborn infant has a high larynx therefore he or she can)t easilymanipulate the frequencies of multiple formants. His or her for-mant frequencies are pretty high because of the short vocal tract.Suppose that a particular infant produces a vowel sound whoseLPC analysis filter is

A(z) = (1 - 0.8z-1)(1 - 0.95ej'I1"/3z-1)(1 - 0.95e-j7r/3z-1)

Assume Fs = 8KHz.

i. Draw a pole-zero plot of the filter H(z) = 1/A(z).ii. What is the first formant frequency, in Hertz?

(b) Classify speech sounds. Give example of each class.

7. (a) Discuss the complex cepstrum, the magnitude cepstrum, and liftering.

(b) With suitable equations and block diagram representation explainhow short-time average zero crossing rate can be determined forspeech signals.

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27 : 2nd half.10-p(d)

Con. 6394-10. (REVISED COURSE)

N.B.: (1)(2)(3)(4)

(3Hours) ,

Question No.1 is compulsory. T~Assume suitable data if necessary. . '" ''''>,.

Attempt any four questions out of remaining six questions.Figures to the right indicate full marks.

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'1. (a) A discretetime invariantand linearsystemis describebythe differenceequation- 10y(n) = x(n) + 2 x(n-1) + x(n - 2 )

Obtain (i) Impulse response(ii) Frequency response

(iii) Sketch magnitude and phase response(iv) System response to the input (- )nn u(n).

(b) Explainthe conceptof decimationby Integer (M) and interpolationby integerfactor(L). 10

2. (a) Find OFT of the sequence using OIT FFT -x [n] = { 1, -2, 2, 2, 1, 3, -3, 4, 5 }

(b) Convert the analog filter with system function-

s+0.1H(s) = I - ~,') - .intoa digitalliR filter using bilineartransformation.The

digital filter should have a resonant frequency of wr = 4 .

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10.

3. (a) A filter is to be designed with the following desired frequency response. 10

{

n0 ; - ~ ~ w- ~ -

Hd(eiW)= 4

(ei2W) ; - ~< Iwi < :Determine the filter coefficients using Hamming window.

(b) Consider a causal LTI system which is defined by system function.

H (z) = 1+ t r'(1+t z-t )(1+ i..;z-t + ~ z2-)

(c) Obtain OF-I, OF-II, cascade and parallel realization structures.

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4. (a) The frequency response of low pass filter is given by-

,

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(ei3W) , 0 S w < ~H(eJW)=-=. )

.0 ) %..s w S 7t

Realize the above filter using frequency sampling realization technique.(b) Develop OIT FFT algorithm for N = 6 = 2.3 using split-radix method.

[ TURN OVER

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28 : 2nd half.10-p(d). .Con. 6394-GT-8904-10.. 2

5. (a) The unit sample response of a system is h[n) = { 3, 2, 1} use overlap-add method 10of linear filtering to determine output sequence for the repeating input sequencex [ n ] = { 2, 0, -2, 0, 2, 1, 0, -2, -1, O}

(b) Explain thesubband coding of speech signal as an application of mutirate signal 10processing.

6. (a) Design a digital Butterworth filter that satisfies the following constraint using 10bilinear transformation Assume T = 1 sec.

0.9S IH(eiW)1 ~1

IH(eiW)1 ~0.2

; Os w ~ 2

. ~<WS1t, 4 -

(b) Draw pole-zero plot and sketch magnitude and phase response of finite impulse 10response fitter which is given by.

h [ n ] = (0.5)'" ; 0 5 n ~ 7

7. Write short note on (any three) :-(a) Multistage approach to sampling rate conversion.(b) Adaptive television echo cancellation.(c) .Goertzel Algorithm(d) Digital resonator.

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A) Enumerateandexplainthe advantage.sand applica~ions.of Microwaves.

B) A 500 transmission Ijne is matched to a.l0V source that feeds a load Zl = 1000. If the line is

2.3A long and has an attenuation constant a=0.5dBA, find the powers that a~edelivered by

the source, lost in the line and delivered to the load.

C) With a neat diagram explain the working of a PINdiode.

D) With a neat block diagram explain the procedure for the measurement of an unknown

impedance at microwave frequencies. .

Q2 20 Marks

A) Usingth~ multiple reflection viewpoint explain the principle of working of a ~uarter wave

transformer.

B) With a neat diagram explain the working of a Magic Tee. Derive its scattering matrix.

Q3 20 Marks

A) Agenerator at 150MHZdrives a 10m long, 750 coaxial line terminated in a composite load

consisting of the parallel connection of two 500 lines oflengths 0.5 m and 1.0 m, each

terminated in a SOOresistance. All lines.are losslesswith Er-=2.2.With reference to figurel,

determine the length Isand connection point d of a parallel-connected 750 stub that will

produce minimum VSWRon the feed line. The stub should be as close .aspossible to the. .

load. (Use Smith Chart)

B) A losslessair-dielectric waveguide for an S-band RADARhas inside dimensions a=7.214 em

and b=3A04 em. For the TMllmode'propagating at an operating frequencythat is 1.1times

the cutoff frequency of the mode, calculate (a)critical wave number, (b)cutoff frequency,

(c)operatingfrequency,(d)propagationconstant, (e) cutoffwavelength,(f)operating

wavelength,(g)guidewavelength,(h)p~asevelocity,(i)wave impedance.

Q4 20 Marks

A) Explainthe workingand derivethe S-Matrixfor a two-holedirectionalcoupler.

B) With neat diagrams explain the working of a Gunn Diode.

[ TURN OVER

N.S. : (1) Question NO.1 is compulsorY'. 'f f\r . .L_ J... (2) Answer any four out of remaining six.

-b... P.M(3) Illustrate answers with sketches.

Iff (4) Use o.fsmith chart is compulsory. N.o\J/f)o

Ql 20 Marks

Q5 \., .

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20 Marks

A) Design.acomposite low-pass filter by the image parameter method with the following

specifications: Ro=500, fc= 50MHz,foo= 52MHz.

B) With suitable diagrams, explain the working of a ReflexKlystron.. . .

Q6 20 Marks

A) Designa low-pass fourth-order maximallyflat filter using only shunt stubs. The cutoff

frequency is 8GHzand the impedance is 500: (Tablefor prototype isgiven below)

B) Atravellingwavetube operates underthe followingparameters:

BeamVoltage:Vo= 3kV

Beam Current: 10=30m A

Characteristic impedance of helix: Zo= 100

Circuit Length: N = 50

Frequency: f = lOGHz. Determine: (a) the gain parameter C (b) the output power gain Ap

in decibels and (c) all.four propagation constants.

Q7.'

20 Marks

A} A plane wave travelling along.the z-axis in a dielectric medium with £r =2.55 has an electric

field given by E =Eocos (wt-kz). The frequency is 2.4GHz, and Eo=30V/m. (a) Find theI. .

amplitudeand directionof the magneticfield(b)Findthe phasevelocityand the Wave

length. Findthe phase shift between the positions zl=0.5m and Zz=1.7m.

B) Brieflyexplain the principle of operation of a gyrotron.

C) Brieflyexplain the concept of Dynamicrange.

D) Explainthe working of a Schottky Diode.t:,=- ~o M

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S L 4. .f'-UV{T>e.P--\DN.S.: (1) Question NO.1 is compulsory. '-\io""" Ml..-J

Ib~ £"1" (2) Attempt any four question out of remaining six que&tio(3) Assume made should be clearly stated.;

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. 1. (a) Relate doppler shift to the mobile velocity and the spatial andirection of motion of the mobile and the direction of arrival of the wave.

(b) Explain the nonlinear effects in FOMA.(c) How is FACCH used for carrying urgent mess~ges ?(d) Derive relationship between capacity C of system and cluster size N.

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2. (a) Elaborateon forwordW-CDMAchannel.(b) How is mobility managed in CDPD ?

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3. (a) Relate 5/1 (signal-to-interference ratio) to the cluster size N. 10(b) A mobile is located 5 km away from a base station and uses a vertical ')../4 10

monopole antenna with a gain of 2.55 dB to receive cellulor radio signals. TheE-field at 1 km from the transmitter is measured to be 10-3 VIm. The carrier

frequency used for this system is 900 MHz.(i) Find the length and the effective aperture of the receiving antenna.

(ii) Find the received power at the mobile using the two-ray ground reflectionmodel assuming the height of the transmitting antenna is 50 m and thereceiving antenna is 1.5 m above ground.

4. . (a) Give an account on 5DMA.(b) Give a complete functional account on N55.

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5. (a) How is power control applied in forward COMA channel. 10(b) The channel data rate is 270.33 kbps in GSM standard that is 40% (say) of 10

theoretical maximum data rate that can be supported in a 200 KHz channelbandwidth. Calculate the corresponding theoretical SIN required.

6. (a) Considera transmitterwhichradiatesa sinusoidalcarrierfrequencyof 1850 MHz. 10For a vehicle moving 60 mph, compute the received carrier frequency if themobile is moving (i) directly toward the transmitter (ii) directly away from thetransmitter and (Hi)in a direction which is perpendicular to the direction of arrivalof the transmitted signal. .

(b) A hexagonal cell within a four-cell system has a radius of 1.387 km. A total of 1060 channels are used within the entire system. If the load per user is 0.029Erlongs, and 'A.= 1 call/hour,computethe followingfor an ErlongC systemthathas a 5% probability of a delayed call.

(i) How many users per square kilometer will this system support ?(ii) What is the probability that a delayed call will have to wait for more

than 10 sec ?

(iii) What is the probability that a call will be delayed for more than 10 sec ?From Erlong C chart, 5% probability of delay with C == 15 corresponds to trafficintensity = 9 Erlongs.

7. (a) How is variable data rate transmission done in reverse COMA channel.(b) Give the 3G COMA evolutionary path.

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