Sixth Semeter

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(Pleasewriteyour Exam Roll No.) Exam Roll No .

END TERM EXAMINATIONSIXTH SEMESTER [B. TECH) MAy - JUNE 2011

IPaper Code: ETEE 302 Subject: Microprocessor ITime: 3 Hours Maximum Marks: 75

1 N_o_t_e._· Q-'.,_N_o_,1_'_'s_c_o_m..!.'P_u_ls_o--,ry~._A_tt_e_m...!.'P_t_o_n_e-,q,--u_es_t_io_n_fl_,,_om_e_a_c_h_u_n_it_,---1Q.l (a) Explain following pins of8085 microprocessor

(i) READY (ii) HOLD(2)

(b) Why lower order address buss (Ao - A7) is multiplexed with Data Bus (Do - 07) andhow it is demultiplexed? (3)

(c) Write any four instructions to clean the contents of accumulator. (2)

(d) How many machine cycles are required for execution of JNC instruction in both thecases when the condition is true or false. (2)

(e) The last address of a 2KB RAM is (FFFF) H what would be the starting address? (2)

(f) Write instruction to configure port A of 8255 as input port in mode-O, Port Basoutput port in mode-l and port c as input port. The address of the control register of8255 is FFH. (2)

(g) Explain the difference between hardware and software interrupts. (3)

(h) Name the command word to be used and indicate the contents of the command wordrequired to configure the 8259 for following operations (2)

a. ICW4 is' to be usedb. Several 8259 are to be used in the systemc. The address interval is required to be 4 bytesd. The IRo.7 requests are to be level triggered. Assume starting address for IRo

routine is 2480H.

(i) In 8086 why memory is organized as 2 byte - wide banks. (4+3)If the code segment for an 8086 program starts at address 70400H, what number

will there in CS Register? Assuming the same code segment base, What physicaladdtress will a code byte be fetched from if the instruction pointer contains 539CH?

UNIT-I

Q.2 Draw and explain the internal architecture of 8085 microprocessor. (12.5)

Q.3 (i) Name all the status and control signals of 8085 microprocessor and explaineach one ofthem. (6)

(ii) Draw the timing diagram for the instructionMOVB,MAssume HL = 2000H

(6.5)

UNIT-II

Northern India Engineering College, New Delhi

[-2-]Q.4 (i) Write 8085 assembly language program to shift a 16 bit binary number l-bit to the

~M. ~

(ii) Write a program to convert a BCD number to binary number. (4.5)

(iii) Explain the following instructions (4)(a) LHLD(b)XCHG(c) XTHL(d) PCRL(e)

Q.5 (i) Write an 8085 assembly language program to divide a I6-bit number by an 8-bit number. Assume that 16 bit number is available at location 2000 and 2001 and8 bit number is at 2002H. Store result at 2003H. (7)

(ii) Write 8085 assembly language program to add two 24-bit numbers. (5.5)

UNIT-IIIQ.6 (i) Inter face 8085 microprocessor with 2K x 8 ROM chip and two lK x8 RAM

chips such that the following address map is realized. (8)Device Size AddressROM 2Kx8 0000-07FFHRAM 1 1x8 IOOO-13FFHRAM 2 Ix8 4000-43FFH

(ii) What do you understand by absolute and partial decoding? Explain withproper example. (4.5)

Q.7 (i) Design the memory interfacing circuit for an 8085 based microcomputersystem having following specifications: (8)

(i) 8K x 8 ROM - One chip(ii) 2K x 8 RAM - 4 chips

Give the memory map. There must not be any fold back memory space.

(ii) Explain, with the helps of proper example, the difference between memorymapped and I/O mapped I/O? (4.5)

UNIT-IVQ.8 (i) Write an 8085 program to generate a continous square wave of 1KHz using

8253. The 8253 is mapped at port address 20H. (5)(ii) What is the difference between synchronous and asynchronous serial transfer?

~~ ~(i) TxRDY(ii) TxE

(iii) Explain specially fully nested mode of 8259 PIC. (3.5)

Q.9 (i) Draw block diagram of 8237 and explain its operation. (5)(ii) Write an 8086 assembly language program to turn on an LED connected to bit3 of port C of 8255. It should be turned off after 1 sec. Assume clock frequency tobe 1 MHz. (4)(iii) Explain whysegment register-in 8086 are also called relocation register? (3.5)

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END TERM EXAMINATION[Paper Code: ETEE304 Subject: Power System-II I

Time: 3 Hours Maximum Marks: 75Note: Attemptfive questions including Q.no.l which is compulsoru. Internal choice is

indicated. Calculator is permitted.

SIXTH SEMESTER [B.TECH.]- MAY 2011

Q 1 Select the most appropriate choice and justify your choice for thefollowing questions:- (2.5xlO=25)(a) The p.u. impedance of a circuit element is 0.15. If the base KVand

base MVA are halved, then the new value of the per unit impedanceof the circuit element will be-(i) 0.075 (ii)0.15 (iii)0.30 (iv)0.60

(b)A balance three phase system consist of-(i) Zero sequence current only(ii)Positive sequence current only(iii)Negativeand zero sequence current only(iv)Zero, negative and positive sequence current.

(c) Series reactors are used to-(i) Improve the transmission efficiency(ii) Improve P.F. of the power system.(iii)Improve the voltage regulation.(iv)Bring down the fault level within the capacity of the switch gear.

(d) In a circuit breaker the current that exists at the instant of contactseparation is called the-(i) Restriking current (ii)Breaking current(iii)Arc current (iv)Recovery current

(e) Air used in air blast C.B. must-(i) Be ionized (ii)Be free from moisture(iii)Have least C02 (iv)Have oil mist

(f) A fuse is-(i) Normally inserted in phase wire(ii)Normally inserted in neutral wire(iii)Never inserted in neutral wire(iv)Never inserted in phase wire

(g) Given rPllII' rP2111=the fluxes produced by the two portions of theshaded pole 8=the angle between «: rP2m' R=resistance of the disc,the torque developed in an induction relay would be proportional towhich of the following:- (A) rPllII' ¢2m (B) IjR (C) R (D) Sine. Selectthe correct answer using the codes given below:-(i) (A),(B)& (D) (ii) (A),(C)& (D) (iii)(A)& (B) (iv)(B)& (D)

(h) For the protection of a 3phase star/Delta transformer the CTs forthe differential relay should be connected.(i) Delta/star (ii)Delta/Delta (iii)Star/Delta (iv)Star/Star

(i) Shunt capacitor in a substation-(i) Consume Lagg. Var (ii)Deliver Lagg. Var(iii)Consume active power (iv)Deliver active power

U) A transmission line is protected by-(i) Distance protection (ii)Inrush current protection(iii)Timegraded protection (iv)Both (i)& (iii)

P.T.O.


[-2-]

Q2 (a)A generating station has two 3 phase alternators, one 12MVA, 20%reactance and the other 8MVA, 24% reactance. Both are rated at6.6KV. The two alternators are connected to 33KV bus barsthrough 6.6/33KV step up transformers, the first through a15MVA, 10% reactance and the second through a 12MVA, 12%reactance. A feeder is taken out from the 33KV bus bars, thereactance of the feeder being 200. A 3 phase dead short circuitfault occurs at the load end of the feeder. The actual generationvoltage of the first generator is 6.6KV while that of the second is6.5KV. Calculate the fault current. (10)

(b)Write short notes on common faults in power systems. (2.5)OR

Q2 The currents flowing in the lines of a balanced load connected in deltaare Ia = 10LOo, lb = 14.14L225° and Ie = 10L900. (12.5)

(a) Show that lahl = is L300 and l"h2 = ] L -300 .(and similarly for

other line and phase currents) where lal and labl are the positiveand la2 and Iab2etc are the negative sequence components of lineand phase currents respectively.

(b)Evaluate the phase current lab from symmetrical components ral,

la2 and Iao of the line current la for the data given above.

Q3 What are the fundamental requirement of a relay? Give theclassification of relays. Describe and define the following terms:- (12.5)(a) Pick up (b)Reset or drop off (c)Drop off/Pick up ratio

ORQ3 Give the differences between a fuse and a circuit breaker. Explain the

working of an air blast circuit breaker with the help of a neat diagram.(12.5)

Q4 Describe with a neat diagram, a circulating current protection schemefor a 3 phase, 1MVA, 11KV / 400V Delta/ star transformer. If thecurrent transformers have a nominal secondary currents of 5A,calculate their ratios. (12.5)

ORQ4 Describe distance protection scheme for the protection of feeders.

Explain why distance protection scheme is superior to other types ofprotection for an over head line. (12.5)

Q5 Explain clearly what do you mean by compensationdiscuss briefly different methods of compensation?

ORExplain with neat diagram the operation of-(a)Thyrister switched capacities(b)Saturated reactor compensator

of line and(12.5)

Q5 (12.5)

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END TERM EXAMINATIONPaper Code: ETEE 306 Subject; Power ElectronicsTime: 3 Hours Maximum Marks: 75Note: Attempt all questions. Internal choice is indicates, Q.No.1 is compulsory. Assume suitable

data if any

Q.l (a) Discuss with help of a diagram the following:(i)DIAC(ii)TRIAC

(5)

(b) Discuss the PWM scheme for inverters (5)(c) Explain the working of single phase to single phase cycloconverters.(5)(d) Explain why serious-turn-off chopper are used for low supply voltage.(5)(e) What is fuse protection? Explain the terms time-current

characteristics and 12trating with respect to operating data of fuse. (5)

Q.2 (a) Explain SCR triggering using IC timmer 555. (6)(b) Discuss the factors responsible for increase of junction temperature

in power semiconductor devices. (6.5)OR

Q.3 (a) What is forced commutation circuit? Discuss class A and class Bforced commutation circuit.

(b) Explain Repetitive overload current rating of SCR.(10)

(2.5)

Q.4 (a) Explain the working of Rectifier with resistive - capacitive load.(b) Discuss the following with proper diagrams

(i)Dual converters(ii)Transformer leakage inductance

(7.5)(5)

ORQ.5 (a) Explain the working of single phase half controlled bridge rectifier

with fly wheel diode and RL load. (7.5)(b) Discuss the working of regulated D.C power supplies using thyristors.(5)

Q.6 What are inverters? Explain with proper waveform working of current.driven inverters. (12.5)

ORQ.7 (a) Explain the working of an inverter with inductive load. (7.5)

(b) With the help of a neat diagram explain the working of a Me-Murraysingle phase inverter. (5)

Q.8 (a) Discuss the working of a Type B chopper. (5)(b) Explain with proper wave form the working of parallel capacitor turn

off chopper. (7.5)OR

Q.9 Explain the following:(i) Four Quadrant chopper(ii)Morgan chopper .

(6.5)(6)


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'. .•.•.. END TERM EXAMIN'ATIONMAY201l

Q4

Q5

Paper.code: ETIT30B Subject: Digital Signal ProcessingTime: 3 Hours Maximum Marks: 75

Note: Attempt one question/rom each unit including Q.no.l which is compulsory. I

Ql (a) Let x(n) = 25(n + 2) - 5(n + 1)+ 35(n) - 5(n -1) + 25(n - 2). Evaluate

(i) X(e1w)ev = a (ii) [X(eJW ~ev (iii) X(eJaJ)ev = 2tr without explicitly

finding X(eJaJ). (6)(b) Find the state variable matrix A, 8, C, D for the input output

relation given by the equation- (5)yen) = 2y(n -1) + 3y(n - 2)+ x(n) + 2x(n -1) + 3x(n - 2) .

(c) Derive the relationship between DFT (i) 2 transform (ii) Fouriertransform of an aperiodic sequence. (4)

(d) Discuss the design of digital resonator. (5)(e) Derive the input and output relation for a system function h(t) if

the input signal x(n) is random. (5)

Q2UNIT-I

(a) Perform the convolution of the following two sequence graphically

h(n)={(ll2)" 0~n~2, x(n)=5(n)+5(n-1)+45(n-2). (6.5)a otherwise

(b) Find the '2' transform the following sequence:- (6)(i) x(n)= n(1I2)nu(n-2) (ii) x(n)=lIn(-2)-"u(-n-l)

Q3 (a) Find the inverse 'Z'transform- (6)

(i) X(Z) = 1+ 114Z-1 ,/Z/ > 2 (ii) X(Z) = I-II 4Z-1

/Z/ > 112(1-II2Z-IY 1+5/6Z-1 +1I6Z-2

'

(b) Compute the DTFT of the following:- (6.5)(i) x(n) = LI(n) (ii) x(n) = Cosoun with UJo = 2tr15.(iii)yen) - 3/ 4y(n -1) + 1/8y(n - 2) = x(n)

UNIT-II(a) Perform the circular convolution and linear convolution for the

input sequence XI (n) = {1,2,3,1,2}x2 (n) = {1,2,3,4}.Discuss the result. (6.5)(b) Determine the DFT of the given data sequence

x(n) = {-1,2,-3,4,9,-20,12,6}usingDIT algorithm. (6)

(a) Prove the following properties of DFT when X(k) is the N point DFT- (6)(i) If x(n) is real and odd.(ii) If x(n) is purely imaginary and odd.

(b) Calculate the IDFT for the given coefficientX(k) = {38, - 5.828 + )6.07, )6, - 0.172 + )8.07, -10, - 0.172 - j8.07, -)6, - 5.828 - j6.07}using DIF structure. (6.5)

P.T.D.


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Q6UNIT-Ill

(a) Eor the following causal linear shift invariant system factorize H(Z)in form H(Z) = H mio (Z)Hap (Z) ,

(i) H(Z) = (1- 3Z-2 XI + O,5Z-1

'1_ 0.75Z-1 \(6)

(b)Consider the random process X(t) = ySinnot + ZCosnot where no isconstant. Y and Z are uncorrelated random variables ieE[Y, z] = E(YJE[ Z] = 0, with zero mean and variance (52. (i)Find meanof X(t) (ii) Auto correlation of X(t). (6.5)

Q7 (a) Explain the sampling theorem inthe design of zero order hold ckt,

(b)Consider a linear shift invariant system, Z-1 *H(Z) = 1- :;1 lal < 1.

(i) Find a difference equation to implement this system.(ii)Show that this system is an all pass system.

(4)

the frequency domain. Discuss(8.5)

with system function

Q8UNIT-IV

(a) Give the system transfer function H(Z) = ( X Z2 -1X ')Z-l/2 Z-1/3 Z-1/4

realize H(Z) as (i)parallel form (ii)cascade form (iii)canonic form. (6)(b) Design the digital butterworth filter satisfying the constraint given

below T=1 using bilinear transformation1112 ~IH(eJOI)I~l for O~OJ~7f/2 (6.5)

iH(eJ(l»i ~ 0.2 for 37f / 4 ~ OJ s n:

Q9 (a) Discuss the properties of Chebyshev polynomial. '. (2.5)(b) Design a high pass filter where the desired frequency response is

given below wit.h t: =3 and OJe = 2rad / S using a window with stop

{e - 101Z OJ < IOJI < 7f

band attenuation -53dB, HAeJOI)= (' - ,- (10)- 0 otherwise

************


(Please write your Exam. Roll No.) Exam. Roll No : ~ .

END TERM EXAMINATIONSIXTH SEMESTER [B. TECH], MAY - 2011

Paper Code : ETEE - 310 Subject: Utilization of Electrical Energy

Time: 3 Hours Maximum Marks: 75

Note: Question No. 1 is compulsory. Attempt remaining 'Iuestions as per choice indicated.

,Q. 1. (a) Explain the factors that must be taken into account whileselecting motor for a particular work. On the basis of thesesuggest drive for

(i) Paper mill

Oi) Cranes

(b) Briefly discuss the special design features of traction motors.

(c) Compare the merits of alternative lighting schemes for usingin candescent lamps, sodium vapour lamps or fluorescent lampsfor industrial lighting.

(5x5=25)

(d) Describe how plugging and rheostatic braking employed withd.c.motors.

(e) Describe with neat sketches the various methods of electricresistance welding.

Q. 2. Discuss in detail how regenerative braking can be obtained withtraction motors.

OR

(12.5)

, , ,

A low frequency indu~tion furnace operating at 10 volts in the econdarycircuit takes, 500 kW at 0.5 pf when the hearth is full. If the econdaryvoltage be maintained at 10 volts, frnd the powerabsorbedand the powerfactor when the hearth is halful. Assume the resistance of the secondarycircuit to be thereby doubled and the reactance is same.

1 P.T.O.


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END TERM EXAMINATIONSIXTH SEMESTER [B.TECH MAy -JUNE 2011

Paper Code: ETEE 312 Subject: VLSI Design & Its ApplicationsTime: 3 Hours Maximum Marks: 75

I Note: Q.No.1 is compulsory. Attempt one question from each unit. I----------------~--~--~--~------------------.

Q.l (a) Described the parasitic effects in MOS device. (4)(b) What will be the output of a chain of pass transistors whose gates are tied to 5V and

input is 3V. Assume VT, passtransistor = O.05V. (2)(c) Explain latchup phenomenon in CMOS technology with suitable diagram. How can it

be avoided? (4)(d) Explain ion implantation (4)(e) Why is pseudoNMOS logic style more suitable for PLA structures. (4)(f) How would you identify PMOS enhancement transistor and depletion mode NMOS

transistor from its characteristics. (3)(g) Draw a schematic of pass transistor based 4: 1multiplexer realization. (4)

UNIT-I

Q.2 (a) Draw energy band diagram of an NMOS structure biased in (i) accumulation (ii)depletion (iii) inversion regions (6.5)

(b) An NMOS transistor with kn = 20).!AN2 and VT = 1.5V is operated with Vgs = 5Vand In = lOO).!A. (6)Determine the region of operation of NMOS and find Vds.

Q.3 (a) What is the need of sizing transistors of an inverter? Compute pull up to pull downratio for a symtnetrical CMOS inverter. (6.5)

(b) Derive an expression for t: PLH for CMOS inverter. (6)

UNIT-II

Q.4 (a) Implement a 4:1 multiplexer with pass transistor logic. Is there any need of sizing thetransistors? (6.5)

(b) Draw a 6 transistor XOR cell and explain its working. (6)

Q.5 (a) Explain the working of dynamic shift register with respect to ratioed and ratiolesslogic. (6.5)

(b) Describe the functioning ofa SRAM memory cell. (6)

UNIT-III

Q.6 What are the steps of fabricating an enhancement mode NMOS transistor, Aid youranswer with suitable diagrams. (12.5)

Q.7 What is electronic grade silicon? Discuss Czochralski crystal growth method in detail.(12.5)

UNIT-IV

Q.& Discuss VLSI description domains and level of design abstraction levels with Y chart.(l2.5)

Q.9 Explain the following terms with respect to chip design: hierarchy, modularity andregularity. Give an example of each. (12.5)


(Please write your Exam Roll No.)BE E J!1.

Exam Roll No ..•................••..

Note: Attempt all questions. Internal choice is indicated.

END TERM EXAMINATIONSubject: Microprocessors

Maximum Marks :75

IQ1 (a) Explain the need of demultiplexing AD7-ADo.How it is done? (3)

(b) Explain the functions of the following signals of 8085 microprocessor(i)HLDA (ii) SO,S1 (iii) 10/ M (iv)INTR. Also state whether the Pinis ainput Pin or output Pin. (4)

(c) What do you mean by PSW? State the application of PSW inprogramming. (3)

(d)Write a subroutine to clear PSW. (3)(e) Interface two input ports at addresses FFFOH and FFFIH and two

output ports at addresses 9000H and 9001H using memory mappedI/O. (3)

(f) Give the status word format for 8255, when its Port A and Port B arein mode-l operation and Port A act as Output Port, while Port Bactas input Port. (3)

(g)What do you mean by maximum mode of 8086? (3)(h) Explain the function of byte enable Pins (BE 0 to if 3) and BS 16Pin of

80386 Microprocessor. (3)

Q2 (a) Give the Pin diagram of 8086 Microprocessor and explain pipeliningand Memory Segmentation. (6.5)

(b)With neat Timing diagram explain memory read cycle and memorywrite cycle. (6)

OR(a) Discuss the register organization of 80386 Microprocessor. (6.5)(b) Explain the descriptor table of 80386 Microprocessor. (6)

Q3 (a) Explain the control word format for 8251. Specify mode word,command word and status word to transmit data with the followingspecifications:- (8)(i) TxC is 153.6KHz (ii)Asyn 9600 baud rate(iii)Character length 5 bits (iv)Two stop bits and no parity check

(b) Explain fully nested mode operation of 8259. (4.5)OR

(a) Give the register organization of 8257 and discuss their use inprogramming 8257. (8.5)

(b) Discuss the use of BSR mode in 8255. Give the control word format toset PC4 and reset PC6. (4)

Q4 (a) Explain the use of RIMand SIM instructions. (6.5)(b) Distinguish between:- (6)

(i) Vectored and non vectored interrupt(ii)Maskable and non maskable interrupt(iii)Software and hardware interrupts

Or(a) Explain the concept of stack memory. How to initialize the stack in

8085 microprocessor. (4.5)

P.T.O.


[-2-]

(b) Calcula;te the time delay produced by following delay pr,ogram:-

Main Program No. of T-statesIN port A lOTMOVD,A 4TCALL DELAY 18TMOVA, D 4TOUT,PORTB lOTHLT. 6T

The subroutine DELAYisDELAY MVI B, 4AH 07T

MYI C, OFH 07TLOOP-1, INR C 04T

MOV A, B 04TSUBC 04TJNZ 'LOOP l' 7/10TRET 01T

(c) What is PSW and state its use? (4)

~/

Q5 (a) List the status signal in 8085. Explain their function. (4.5)(b) Explain with schematic diagram how separate address and data

51'gnal can be generated from 8085 common address-data lines. (4)(c) Explai!\ the function of (i) HLDA (ii) RESET OUT (iii) SOD (iv) So Pin

of 8.085 Microprocessor. (4)OR

(a) Whatl are RAMs and ROMs? Why should both of these be used in an8085 ,Microprocessor system? . (4.5)

(b) List the control signals of 8085 Microprocessor and explain theirfunction. (4)

(c) How ~des Microprocessor differentiate between data and Instruction? (4)• t ************i

I 1Northern India Engineering College, New Delhi

(Please write your Exam Roll No.) Exam Roll No .

END TERM EXAMINATIONPaper Code: ETEE304 Subject: Power System-IIPaper Id: 49304Time: 3 Hours Maximum Marks :75

I Note: Attempt one question from each unit including Q.1 which is compulsory.

Q1 (a) What are the advantages of p.u.system? (2.5x10=25)(b) Explain the effects of short circuit in a power system.(c) Why is 3-phase symmetrical fault more severe than a 3-phase

unsymmetrical fault?(d) Explain breaking capacity of a circuit breaker.(e) What is the difference between a fuse and relay?(n Explain the term Plug setting multiplier and Time setting multiplier in a

relay.(g) Explain earth fault protection for alternator.(h) What are advantages of shunt compensation in a transmission line?(i) What is the basic principle of operation of surge divertor?(j) What are advantages of FACTS devices used in power system?

UNIT-IQ2 (a) Why do we use reactors in the power system? Discuss their advantages. (6)

(b) The plant capacity of a 3-phase generating station consists of tur 10,000kVA generators of reactance 12% each and one 5,000 kVA generate ofreactance 18%. The generators are connected to the station bus bars fromwhich load is taken through three 5000kVA step up transformers eachhaving a reactance of 5%. Determine the maximum fault MVA which thecircuit breakers have to deal on (i) low voltage side (ii) high voltage side. (6.5)

Q3 A 15MVA, llkV, 3-phase synchronous generator with a solidly groundedneutral has a subtransient reactance of 25%. The negative and zero sequencereactances are 35% and 10% respectively. Determine the subtransient currentsand line to line voltage at the fault under subtransient condition when a doubleline to ground fault occurs at the generator terminals. Assume that generator isoperating on no load and at rated voltage. (12.5)

UNIT-IIQ4 (a) Explain the construction and principle of operation of a Reactance relay. (6)

(b) Describe the construction, principle of operation and applications of HRCfuse. (6.5)

Q5 (a) Explain various rating of circuit breaker. (6)(b) Describe the construction, principle of operation and applications of SF6

circuit breaker. (6.5)

Q6

Q7

UNIT-III(a) Describe the construction, principle of operation and

Buchholz relay.(b) Describe the rotor protection against earth fault.

(a) Describe the construction and working of valve type arrestor.(b) Explain carrier current protection.

applications of(6.5)

(6)

(6.5)(6)

Q8UNIT-IV

(al Explain the advantages of series compensation in a power system.(b) Explain the need of reactive power management in a power system.

(6)(6.5)

Q9 Explain the various types of shunt FACTS controllers.applications and limitations.

************

Discuss their(12.5)


(Please write your Exam Roll No.) Exam Roll No •...••..•••.••••••••..•

END TERM EXAMINATIONSIXTHSEMESTER B.TECH. MAy-20lO

Paper Code: ETEE306 Subject: Power ElectronicsTime: 3 Hours Maximum Marks :75

Note: Q.1 is compulsory. Attempt remaining questions as per choice indicated. IQ1 (a) A thyristor requires lOvolts to be fired. If the load line has a slope of -

lOOv/amp, find the gate current when the trigger source has amagnitude of 12volts dc supply. (3)

(b)A thyristor is rated for 440V PlY. Obtain the voltage for which thisthyristor can be operated for voltage safety factor of 1.8. (3)

(e) Why gate current ceases automatically once the thyristor is tunredon? (3)

(d)What will be the value of the dc output current and its correspondingac value for a fullwave rectifier supplying a load of 2KO from an acsource of 1OOsin314t volts. (3)

(e) Discuss the role of free wheeling diode in controlled rectification. (3)(f) In a cyclo converters what is the relation between triggering angles of

the thyristors of bilateral converters and why? (3)(g)Explain the effect of source inductance on the commutation process of

phase controlled rectifier. (3)(h)A step up chopper supplies a load of 480V from a 230V dc supply.

Assuming the non conduction period of the thyristor to be 5011sec,find the on time of thyristor. (4)

Q2 (a) Draw static and dynamic equalizing circuits for thyristor in seires andexplain their operation. (6)

(b)A thyristor circuit has an input voltage of 300V and load Resistance oflOohm. The circuit inductance is negligible. The operating frequency

of the circuit is 2KH~. The required dv is lOOVIllS and dischargedt

current is to be limited to 100A. Find- (6.5)(i) Snubber circuit R and C(ii)Power rating of R of snubber circuit.(iii)Powerloss in snubber circuit.

ORQ3 (a) What is triace? How is it different from thyristor? Explain the modes

of operation of thyristor. (6)(b)A 120A, SCR Sl is in parallel with another 150A 8CR S2, SCR 81 has

on-state voltage drop of 1.5V while SCR S2 has the voltage drop of1.2V. Determine the value of the resistance to be inserted in serieswith each SCR so that they can share a total load of 270A inproportional to their current rating. (6.5)

Q4 (a) Explain the operation of half controlled bridge with resistive load andfind the expression for, average load voltage and load current. Howdoes the operation get modified with R-L load? (6)

(b)A six pulse thyristor converter, connected on the secondary of11KV1700V, 50Hz transformer is supplying to 750V, 200A dc load.Calculate- (6.5)(i) Converter firing angle.(ti)de power delivered by the converter.(iii)ACterminal power(iv)ACline current P.T.O.

~,


Q5

[-2-]

(v) Brahch current through the device.OR

(a) Explain the' working of a single phase bridge type cyc1oconverter.Draw the input wave of frequency f and output wave of frequency fj3for RLload. (6)

(b)A single phase full wave regulator has an input voltage of 230V, 50Hz.It feeds a load having R=5 0 and L=20mH. Find (6.5)(i) Control range of frring angle(ii)Conduction period for each thyristor if a = e .(iii)Maximum possible rms load current.

(a) How' is it possible to construct a transistorized three phase bridgeinverter usirtg six transistors? Describe the operation for 1800 mode of

,'conduction. Derive expression for line and phase voltage. (6), (b)A single 'phase'fUll bridge inverter has a resistive load of R=100 and

the DC input voltage of 1,00V.Find (6.5)(i) RMS output voltage at fundamental frequency.(ji) Output power Pout.(iii)Peak and average current of each thyristor.(iv)PIVofeach thyristor.

Q6

Q7t.

OR(a)'Draw:a neat diagram of McMurra-Bed force half bridge inverter.

• i 'Explain its operation with the help. of voltage and current waveform. (6)(b)Write short notes on the following:- (6.5)

(i) Reversible converter (ii)UPS .II

Q8 (a) How are choppers classified? Show the quardrants of operation ofdiffereht choppers. Draw their circuit and explain their workingbriefly:' (6)

(b)A stepl down choppers feeds a dc series motor from a 550V dc system .. '! The ~ature and field resistance of the motor being 0.030 and 0.020

i', the av~ragecurrent in motor circuit being 300A, the chopping periodbeing il0311sec. Calculate the pulse width if average value of back emfis 300V. (6.5)

I ORQ9 Write short notes on the following:- (6.5+6)

(a) Multiquadrant choppers(b) Analysis of chopper circuits

• ••l ;/. :1-" (J,','1;"

!

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Exam Roll No .(J)END TERM EXAMINATION

(Please write your Exam Roll No.)

SIXTH SEMESTER B.TECH. MAY-2010Paper Code: ETiT/ETIC/ETEE30B Subject: Digital Signal ProcessingTime: 3 Hours Maximum Marks :75

I . Note: Attempt one question from each unit including Q.1 which is compulsory. IQl (a) Define DFT of a periodic sequence x(n) with length N of its period.

Derive the expression to obtain the sequence x(n) from its DFT X(k).(4)(b)Give the sequences defining at least five different window functions

w(n), commonly used in FIR fl1ter designer. (4)(c) Define the Chebyshev polynomial CN(X).Obtain the recursive relation

to build up higher order Chebyshev polynomials. (4)(d) Obtain DTFT for x(n)=u(n). (4)(e) An FIR digital filter satisfies the condition h(n)=h(N-l-n), where h(n) is

it impulse response and N is its length. Determine H(e'w) if N is anodd integer. (4)

N(~ _I ~(f) H(z)::;:--Is an all pass filter. If N(z)=ao +ajz +a2z and aO, aI, a2D(z)

are real constants, what will be the expression for D(z)? Justify youranswer by proof. (5)

UNIT-IQ2 (a) Find the z transforms, gIVIng ROC In each case

(i) x(n)=sinnwo·,u(n) (ii) x(n)=-anu(-n-l). (3+3)

(b) Find inv~rse z-transform given X(z) = log(1- 2z), Izi < ~. (3)

(c) Determine the frequency response of the system characterized by

yen) = (5/ 6)y(n -1) - (~)y(n - 2) + x(n) . (3.5)

(4)X(eJ"') is also real and

(4)

(4.5)""

(c) Find the DTFT of the periodic sequence given by Io(n-kN).k=-«>

?. "" 1 1C -

(a) Show that 2:\x(nt =- fIX(eJW)\ dw.11=-«> 21r -1C

(b) If x(n) is real and even show that its DTFT,even.

Q3

Q4UNIT-II

(a) Define circular convolution of two periodic sequences Xl (n) and X2 (n) .

Show that x1(n) N x2(n) gives DFT as X](k).X2(k) . (3)(b) If x(n)DFTX(k), find the DFT ofX(n). (3)(c) Why FFT is so important? What are its advantages? Develop the DIT-

FFT algorithm. Draw the complete flow diagram taking sequencelength N=8. (6.5)

Q5 (a) Given th~ ~ystem function: H(z) = Z-I(l+3z-1

+4z-2

)

1+7z-1 +6z-2 +5z-3

vclriabte ;~{-B~'Cland 12."'-,---

find the state'

(4)P.T.O.

~\


asmatrices

the correspondingFind

variable[-2-]

state(b) Give

A=[O- -2system function H(z). (2)

(c) Explain briefly the sampling techniques; the impulse sampling, thenatural top sampling and the flat top sampling. Give circuits howthese are realized. Also, explain the merits and demerits of each ofthese techniques. (6.5)

UNIT-IIIQ6 (a) Design a linear phase FIR filter, given the desired frequency response

{e - j4", - Jr /6 < W < Jr /6

L','"j' Hd(e/"') = - - . Use Hann window. Determine theo otherwiseresponse h(n) for the causal design. (8.5)

(b) Realize' the system function as cascade, parallel and canOnIC

structures, given H(z) = ( X z' X ) . . (4)1"-~z-1 1-~z-l l-~z-I

632

Q7 (a) Derive the relation for bilinear transformation connecti;ng s-domainand the z-domain. Show the mapping of points in s-domain to z-domain. (6.5)

(b) By using Impulse Invariant Response, transform the analog filterb

Ho(s) = ( )2 to H(z). (3)s + a + b2

(c) Define minimum phase and maximum-phase filters current,

(l-lz-I )6-5Z-I)H(z) = ------- into the form H(z)=Hmin(Z).Hall(z). Where

(1 -11( 1 -I)1-'2z ) 1-4z

Hmin(Z) isa minimum phase and Hall(z)is an all pass filter. (3)

use bilinear transformation

Q8UNIT-IV

(a) Design a digital Butterworth filter, meeting the specifications:-Password 0.8::; /H(el"')I::; 1 0.7Jriw/::; Jr

stop band jH(ejW) ::; 0.21 0::; iw!::; 0.2Jr

and"take T=l. (8)(b) Give the frequency transformation to transform a lowpass filter with

pass band 0 to ep to a high pass filter, with pass band wp to Jr. Derive

the value of a in terms of ep and Wp. (4.5)

"f ,"

1·, [''/i

Q9 (a) For a finite length Register with b+1 bits and the rounding off as thequantization method, find the . (4)(i) mean me of the quantization error e(n),(ii)Variance 0"/ of the quantization error e(n).

(b) rrthe above error signal is 'passed through a digital system h(n). Whatwould be the mean and variance of the output sequence? (4)

(c) For a random sequenCe x(n), how do we compute its Power SpectrumDensity (PSD)? Assume the random process as stationary and isergodic in the first and second moments. (4.5)

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(Please write your Exam Roll No.) Exam Roll No••..••.•..••••••••••.••

Sample size of materialPower absorbed by samplePermittivity of materialAbsolute permittivitySupply voltagePower factor

END TERM EXAMINATIONSIXTH SEMESTER B.TECH. MAy-lOlO

Paper Code: ETE1E310 Subject: Utilization of Electrical EnergyTime: 3Hours Maximum Marks :75

Note: Q.1 is compulsory. Attempt remaining questions as per choice indicated. IQ1 (a) Distinguish between Resistance Welding and Electric Arc Welding. State

advantages of each. (5x5=25)(b) Enumerate important parameters of a motor's specifications.(c) Draw electric Block-diagram of an electric locomotive and state function of

each part.(d) Given 4-types of lamps Le.(i) Incandescent lamp (ii) sodium vapour lamp (iii)

Mercury vapour lamp and (iv)Fluorescent Tube, which one would you selectfor street lighting? Give reasons.

(e) Discuss the process of "plugging" as applied to 3-<1>Induction motors.

Q2 Find the frequency of the supply source used for heating an insulating materialstate from the following data:- (12.5t

20x20x2.5cm3

500W48.854xlO-12F 1m2000V0.05OR

State various methods of electric-braking. Explain anyone method in detail. (12.5t

Q3 Explain speed-current and torque-current characteristics of a D.C. series~~ (U~

ORExplain different welding processes under "Resistance-Welding". Why it isnecessary to use a welding transformer? (12.5t

Q4 Compare fluorescent Tube, sodium vapour lamp and a filament lamp on thebasis of Initial cost, operational cost, and quality of light, efficiency and averagelife. (12.5t

OR(a) State advantages and disadvantages of individual vs Group Drives. (6t(b) Distinguish between ACIDC drives. (6.5t

Q5 (a) Name various systems of Track-electrification. Which system is mosteconomical and why? (12.5)

(b) Electric train movement data is as under:-

Distance between two stations 1.5KmTime per stop 26sec.Acceleration 0.8KmphpsRetardation 3.2kmphpsRatio of maximum avera e s ed 1.3Find 'Schedule-Speed'. Assume Trapezoidal speed-time curve.

OR(a) Enumerate advantages of electric traction. (4t(b) Explain a typical speed-time curve of motion of an electric train. (5t(c) State advantages of coated electrodes. (3.5)

***"'''''''''''''''''''**


(Plellse write your Exam Roll No.) Exam Roll No .

END TERM EXAMINATION__________ ~S_I_XT_H_S_E_I\1!ST.~~(B.TECH.( MAY-10)_O .

[~~J;jrc,C!?e:ETEE312 ~S_ub_'i_ec:t:_,!LSlpesign & Its Applfcation ~Time: 3 Hours Maximum Marks :75----- ------------- ..- ]L_ Note: Attempt any five questions.

Q1 (a)With the help of energy band diagram explain the operation ofMOSFETunder external Bias. (8)

(b)What is flat band voltage? Why band bending takes place at oxidesemiconductor interface? (7)

Q2 (a) Explain depletion and enhancement mode transistors. Which type ispreferred in VLSIand why? (7)

(b)Consider the following P-channc1 MOSFET process. Substratedoping=1015cm-3, polysilicon gate doping density=102ocm-3, gate oxidethickness=650A, oxide interface charge density=2xl01ocm-2. Usecsi,-,I1.7co and Cox--' 3.97cofor the dic1ectric co-efficients of silicon andsilicon-dioxide respectively.(i) Calculate the threshold voltage for zero body bias.(ii)Determine the type and the amount of channel ion implantationwhich are necessary to achieve a threshold voltage of -2volt. (8)

Q3 (a) Explain the operation of CMOS Inverter. Give various operatingregions and the corresponding critical input and output voltage levels.(7)

(b)Derive the equations of Inverter delay. (8)

Q4 (a) Determine pull-up-to pull down ratio for an nMOS inverter driven byanother nMOS inverter. (8)

(b)Determine function F. (7)

~Q5 (a) Give one example of eaeh CMOSlogic.

(i) AOIlogic circuit (ii)OAIlogic circuit(b)Explain the process of photolithography.

Q6 (a)What are the advantages of ion implantation over diffusion? With thehelp of a neat diagram explain the working of an ion implanter. (8)

(b)Explain sputtering method of metallization. (7)

Q7 (a) Differentiate between synthesis and simulation tools. (8)(b)What are various criteria to be considered for design quality? (7)

Q8 (a)What are various design methodologies ofVLSI circuit? (7)(b)Explain crystal growth and wafer preparation process. (8)

Q9 Write short notes on any three of the following:- (5x3=15)(a) Epitaxy (b) CMOS register (c)MOS switch(d) PLAs (e)Twin-tub process

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Sixth Semeter