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Multiple Choice Questions

Total MarksDuration

v: 50: 90 Minut~s

Instructions:(a) Select the most appropriate answer from four options given.(b) Q-l to Q-20 1marks each. Q-21 to Q-35 --- 2 marks each.

(1)

(2)

(3)

(4)

(5)

(6)

If the fourier transform of deterministic function get) is G(t) then theFourier transform of g(t-2) is

(a) G(t)e-j47ff(b) G(2t)(c) 2G(2t)(d) G(f-2)

Double integration of a unit step function would lead to(a) An impulse(b) A parabola(c) A ramp(d) A doublet

A waveform with discontinuities is always characterized by(a) Fast converging line Fourier spectra(b) Strong harmonic constant(c) Half wave symmetry(d) Quarter wave symmetry

The autocorrelation function ~( T ) of a signal X(t) = Vsin OJt is given by1

(a) -V2COSCOT2

(b) V2 COSCOT

(c) V2 cos2 COT

(d) 2 V2 cos2 OJT

The Probability Density Function of the envelope of narrow band noise is(a) Uniform(b) Gaussian(c) Rayleigh(d) Rician

The infrared LED is usually fabricated from(a) Ge(b) Si(c) GaAs(d) GaAsP

- 1-

~(8)

(9)

(10)

(11)

(12)

(13)

(14)

The power dissipation at the collector is zero in the quiescent state andIncrease with excitation in the case of

(a) Class A series fed amplifier(b) Class A transistor coupled amplifier(c) Class AB amplifier(d) Class B amplifier

If a =0.98, Ieo = 6 Ii A, IB= 100Ii A for a transistor, then the value of IeWill be

(a) 2.3 mA(b) 3.1 mA(c) 4.6 mA(d) 5.2 mA

Which of the following is not a weighted code?(a) 8421 code(b) Excess 3 code(c) 2421 code(d) Hex code

Ifn has the value 3, then the statement a[++n] =n++;(a) Assigns 3 to a[5](b) Assigns 4 to a[5](c) Assigns 4 to a[4](d) What is assigned is compiler dependent

The image channel rejection in a superhetrodyne receiver comes from(a) IF stages only(b) RF stages only(c) Detector and RF stages only(d) Detector, RF and If stages

An increase in modulation index leads to increase in bandwidth in case of(a) AM(b) FM(c) PM(d) None

The post fix equivalent of the prefix *+ab-cd is(a) ab+cd-*(b) abcd+-*(c) ab+cd*-(d) ab+-cd*

How many four digit numbers greater then 3000 can be made from2,2,3,3,3,4,4,4,4?

-2-

(15)

(16)

(17)

(18)

(19)

(20)

(a) 45(b) 54(c) 51(d) 52

If the carrier of a 100% modulated AM wave is suppressed, thePercentage power saving will be

(a) 50(b) 150(c) 100(d) 66.66

IfrLe= 1O(-I+i) then e =(1+i) , -

(a) 135(b) 45(c) 90(d) 0

Fora given op-amp, CMRR = 105and differentia gain = 105.what is theCommon mode gain of the op- amp?

(a) 1010(b) 2x 105(c) 105(d) 1

In the circular waveguide with radius 'r', the dominant mode is(a) TMol(b) TEol(c) TMll(d) TEll

The relationship between SWR and Kr of a transmission line is

(a)SWR=K,+1K -I,

(b) SWR= I-K,I+K,

(c) SWR = I+K,l-K ,

(d) SWR = K;+1l-K' ,

HDLC is an acronym for(a) High Duplex Line Communication(b) High-level Data Link Control(c) Half duplex Digital Link Combination(d) Host Double Level Circuit

- 3 -

(21)

(22)

(23)

(24)

(2S)

(26)

The current i(t) flowing through a resistor R=lO Q isi(t) = SsinlVt + 4sin3 lVt + 3sinS lVt.Then average power is

(a) 160W(b) 2S0W(c) SOOW(d)now

An FM radio receiver is tuned to a 90.6 MHz broadband station. It willReceive an image frequency of

(a) 1l0MHz(b) 112MHz(c) 114MHz(d) 120MHz

The Nyquist sampling time for signal get)= 10cos(SOnt)cos2(lS0nt),Where 't' is in seconds, is

1(a) -sISO

1(b) 200 s

1(c) -s300

1(d) -s

3S0. S2-Ss+100

ThetransferfunctIOnH(s) = 2 represents,s +Ss+100(a) A High Pass(b) A Band Elimination Filter(c) A Resonator(d) An all pass filter

Which of the following is ROC for sequence

x[n]= bnu(n)+b-"u(-n-1);lbl <1

(a) Region Izl< 1

(b) Annular strip in the region b > Izi> ~b(c) Region Izi > 1

(d) Annular strip in the region b < Izi< ~b

In transistor, hfe= SO,hie= 830 ohm, hoe= 10-4. Its output resistanceWhen used in CB configuration is about

- 4-

(27)

(a) 2MQ(b) 700KQ(c) 2.5MQ(d) None of the above

In n-channel JFET has a pinch-off voltage ofVo = -5V, VDs(max)= 20V,gm= 20mAN. The minimum 'ON' resistance is achieved in the JFET for

(a) VGs=-7V and VDs= OV(b) VGs= OV and VDS= OV(c) VGs=OVandVDs=20V(d) VGs= -7V and VDS= 20V

(29)

(30)

The content of Accumulator just after execution of the ADD instruction inLine 4 in an 8085 microprocessor will be

Line 1: MVI A, B5HLine 2: MVI B , OEHLine 3: XRI 69HLine 4: ADD BLine 5: ANI 9BHLine 6: CPI 9FHLine 7: STA 30lOHLine 8: HLT

(a) C3H(b) EAH(c) DCH(d) 69H

A memory system of size 32 Kbytes is required to be designed usingMemory chips which have 12 address lines and 4 data lines each. What isthe number of such chips required to design the memory system?

(a) 4(b) 8(c) 16(d) 32

- 5 -

(28) Match the list:List I List IIA. Diode 1. Pinch-off VoltageB.SCR 2. Holding CurrentC.BJT 3. Forward ResistanceD.FET 4. Active Region

A B C D(a) 3 4 2 I(b) 1 2 4 3(c) 3 2 4 1(d) 1 4 2 3

(31)

(32)

(33)

In the circuit shown in the given figure, the current flowing throughresistance of 100 ohm would be

(a) SmA(b)lOmA(c) 20mA(d) 100mA

The Differential amplifier has inputs, VI = 1050f.lV and V2 = 950 f.lVwith CMRR = 1000. The error in the differential output is

(a) 10%(b) 1%(c) 0.1%(d) 0.01%

Match the following:List II) TCON2) SBUF3) TMOD4) PSW5) PCON

List IIi) contains status informationii) timer / counter control register.Hi) idle bit, power down bitiv) serial data buffer for Tx and Rx.v) timer/ counter modes of operation.

(a) I->ii, 2->iv, 3->v, 4->i, 5->iii.(b) I->i, 2->v, 3->iv, 4->iii, 5->ii.(c) I->v, 2->Hi,3->ii, 4->iv, 5->i.(d) I->iii, 2->ii, 3->i, 4->v, 5->iv.

-6-

J<> IK<>

I+IOVI

f'...,,---l

II

2V --t + 1,-IOV

< 100ohm<,

-L

(31)

(32)

(33)

In the circuit shown in the given figure, the current flowing throughresistance of 100 ohm would be

(a) SmA(b)1OmA(c) 20mA(d) 100mA

The Differential amplifier has inputs, VI = 1050flV and V2 = 950 flVwith CMRR = 1000. The error in the differential output is

(a) 10%(b) 1%(c) 0.1%(d) 0.01%

Match the following:List I1) TCON2) SBUF3) TMOD4) PSW5) PCON

List IIi) contains status informationii) timer / counter control register.Hi) idle bit, power down bitiv) serial data buffer for Tx and Rx.v) timer/ counter modes of operation.

(a) l->ii, 2->iv, 3->v, 4->i, 5->iii.(b) l->i, 2->v, 3->iv, 4->iii, 5->ii.(c) l->v, 2->Hi,3->ii, 4->iv, 5->i.(d) l->iii, 2->ii, 3->i, 4->v, 5->iv.

- 6 -

J<> 1K<>

I+10V

f'...,,---l

II

2V --t + 1,-10V

"-<: 100ohm<,

-L

(34) 8096 has following features fill up the following,i) - Register file,ii) - I/O Portsiii) - architecture.

a) 256 byte, five 8bit, register to registerb) 256 byte, four 8bit, register to registerc) 232 byte, five 8bit, register to registerd) 232 byte, six 8 bit, register to register

(35)s+2 S2+1

Given that L[f(t)] = S2 +1' L[g(t)] (s+3)(s+2)(

h(t) = ff(Og(t- Ode:;, then L[h(t)] is,0

(a) s' +1s-3

(b) ~s+3

( )S2+ I s + 2

c +-(s+3)(s+2) s2+1

(d) None

- 7 -

~jJ'&L KEYS:(I" - (1) a(2) b(3) b(4) a(5) b(6) d(7) d(8) d(9) b(10) d(11) b(12) b(13) a(14) c(15) d(16) c(17) d(18) d(19) c(20) b(21) b(22) b(23) d(24) d(25) a(26) d(27) c(28) c(29) c(30) c(31) a(32) b(33) a(34) C(35) b

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