ISRO Scientist or Engineer Electronics 2008

ISRO Scientist or Engineer Electronics 2008 - Question 1

Report

The circuit shown in figure is a

A

Low-pass filter

B

High-pass filter

C

Band-pass filter

D

Band-reject filter

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 2

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In the op-amp circuit given in figure, the load current $$i_L$$ is

A

$$-\frac{v_s}{R_2}$$

B

$$\frac{v_s}{R_2}$$

C

$$-\frac{v_s}{R_L}$$

D

$$\frac{v_s}{R_1}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 3

Report

An op-amp has an offset voltage of 1 mV and is ideal in all other respects. If this op-amp is used in the circuit shown in figure, the output voltage will be

A

1 mV

B

1 V

C

$$\pm$$ 1V

D

0 V

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 4

Report

For the circuit shown above if $$g_m = 3 \times 10^{-3}$$ and $$R_s = 3000 Ω$$, thenn the approximate value of $$R_o$$ is

A

3000 Ω

B

1000/3 Ω

C

300 Ω

D

100 Ω

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 5

Report

Where does the operating point of a class-B power amplifier lie?

A

At the middle of ac load line

B

Approximately at collector cut-off on both the d.c and a.c load lines

C

Inside the collector cut-off region on a.c load line

D

At the middle point of d.c load line

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 6

Report

The Laplace transform of $$e^{-2t}$$ is

A

$$\frac{1}{2s}$$

B

$$\frac{2}{s}$$

C

$$\frac{2}{s + 1}$$

D

$$\frac{1}{s + 2}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 7

Report

The system with characteristic equation $$s^4 + 3s^3 + 6s^2 + 9s + 12 = 0$$

A

Stable

B

Unstable

C

Marginally stable

D

Marginally unstable

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 8

Report

Compared to field effect photo transistors, bipolar photo transistors are

A

More sensitive and faster

B

Less sensitive and slower

C

More sensitive and slower

D

Less sensitive and faster

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 9

Report

The output VI characteristics of an enhancement type MOSFET has

A

Only an ohmic region

B

Only a saturation region

C

Anohmic regionat low voltage value followed by saturation region at higher voltages

D

Anohmicregionat large voltage values preceded by a saturation region at lower voltages

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 10

Report

Which of the following relation is valid?
Where MTBF = Mean Time Between Failures
MITTF = Mean Time To Failures
MTTR = Mean Time To Repair

A

$$MTBF = MTTF + MTTR$$

B

$$MTTR + MITF + MTBF = 1$$

C

$$\frac{1}{MTTR} + \frac{1}{MTTF} + \frac{1}{MTBF}$$

D

$$MTBF . MITF . MTTR = 1$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 11

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Two transistors have the same value of $$\alpha$$ but different gain bandwidth products. One of them is a germanium transistor and the otheris a silicon transistor. Both the transistors have similar geometries and base width. The transistor with lower GB product

A

is the germanium

B

is the silicon

C

both are same

D

Cannotbe identified unless more information is available

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 12

Report

The following transistor configuration has the highest input impedance

A

CC

B

CE

C

CB

D

All of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 13

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If $$t_c$$, h and $$t_m$$ specify the cache access time, hit ratio and main memory access time then the average access time is (given $$t_c = 160 ns, t_m = 960 ns, h = 0.90$$)

A

160 ns

B

960 ns

C

256 ns

D

960 $$\times$$ 0.9 ns

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 14

Report

The advantage of write (copy) back data cache organization over write through organization is

A

Main memory consistency

B

Write allocate on write miss

C

Less memory bandwidth requirement

D

Higher capacity

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 15

Report

$$E^2PROM$$ storage element is

A

Cross — coupledlatch

B

Isolated gate transistor

C

Capacitor

D

Flip flop

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 16

Report

The modulus of $$1 + \cos \alpha + i \sin \alpha$$ is

A

$$2 \sin \frac{\alpha}{2}$$

B

$$2 \cos \frac{\alpha}{2}$$

C

$$\sin^2 \frac{\alpha}{2} - 1$$

D

$$\cos^2 \frac{\alpha}{2} - 1$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 17

Report

The 8 bit DAC produces 1.0 V fora digital input of 00110010. Whatis the largest outputit can produce?

A

5 V

B

-5 V

C

5.5 V

D

5.10 V

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 18

Report

The fastest ADC amongthe following is

A

Successive approximation type

B

Dual slope type

C

Sigma — Delta ADC

D

Flash converter

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 19

Report

The mod numberof a Johnson counterwill be alwaysequalto...... the numberofflip flops used

A

same

B

twice

C

$$2^N$$ where N is the number of flip flops

D

None of these

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 20

Report

Odd parity generator uses ............ logic

A

XNOR

B

XOR

C

Sequential

D

OR

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 21

Report

Which type of memory has fast erase and write times

A

EPROM

B

EEPROM

C

Flash memory

D

None of these

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 22

Report

The performancegain that can be obtained by improving someportion of a computer can be calculated using

A

Moore’s law

B

Djikstra’s algorithm

C

Amdahl’s law

D

Murphy’s law

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 23

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Micro programming refers to

A

Emulation

B

Programming at micro level

C

The use of storage to implement the control unit

D

Array processing

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 24

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An array processor is a ........ machine

A

SIMD

B

MIMD

C

SISD

D

MISD

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 25

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............... machines tend to make useofinternal resources of the processor, a rich set of registers and a pipelined organization.

A

CISC

B

Parallel processors

C

RISC

D

Array processor

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 26

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Difference between a switch and Hub

A

Both are same

B

Switch avoids flooding

C

Hub avoids broadcast

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 27

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100 Base T refers to

A

Fibre connectivity

B

BNC connectors

C

SONET

D

Twisted pair

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 28

Report

A S-R flip flop with a clock input can be converted to a ‘D’ flip flop using

A

Two inverters

B

the flip flop outputs (Q & $$\overline{Q}$$) connected to its inputs (S & R)

C

One inverter

D

Not possible

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 29

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An 8 bit ADC hasa full scale input of 2.55 V. If other cumulative errors are 2.55 mV, determine the maximum error

A

10 mV

B

12.55 mV

C

7.45 mV

D

2.55 mV

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 30

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A counter is designed withsix stages of flip flops. Determine the output frequencyat the last (sixth) stage, when input frequency is 1 MHz.

A

1 MHz

B

166 MHz

C

15.625 MHz

D

zero

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 31

Report

The ethernet protocol uses

A

$$\frac{CSMA}{CA}$$

B

SCPC

C

$$\frac{CSMA}{CD}$$

D

Slotted ALOHA

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 32

Report

The value of c which makesthe angle $$45^\circ$$ between $$\overline{a} = i + cj$$ and $$\overline{b} = i + j$$ is

A

1

B

$$\frac{1}{\sqrt{2}}$$

C

$$\frac{-1}{\sqrt{2}}$$

D

0

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 33

Report

In a daisy chained connection to the CPU,the peripheral whose interrupt request has the highest priority is the one

A

With the largest vector address.

B

With highest speed of operation

C

Electrically nearest to the CPU

D

Electrically farthest from the CPU

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 34

Report

RS-232 interface

A

Uses only positive voltage

B

Cannot transmit signals over long distance

C

Uses only negative voltage

D

A logic high usespositive voltage

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 35

Report

Assuming ideal conditions, the speed up obtained from a balanced N stage pipeline is

A

2 N

B

N$$^2$$

C

N

D

N!

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 36

Report

The number of comparators required in an 8-bit flash-type A/D converter is

A

256

B

255

C

9

D

8

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 37

Report

Minimum numberof 2-input NAND gates that willbe required to implement the function: Y = AB + CD + EF is

A

4

B

5

C

6

D

7

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 38

Report

In a ripple counter how many changes in state happen when count changes from 7 to 8?

A

1

B

2

C

3

D

4

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 39

Report

A programmable device (PROM) is

A

programmable OR and fixed AND array

B

programmable ANDand fixed OR array

C

programmable AND and programmable OR array

D

none

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 40

Report

In asynchronous circuits, which of the following best explains a dynamic hazard

A

Output changes several times for a single change in an input

B

Output changes to a different state for a single change in an input

C

Output changes momentarily when it is supposed to remain constant for a single change in an input

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 41

Report

Digital signal processors use a computer architecture derived from

A

Harvard Architecture

B

Von-Neumann Architecture

C

Cray Architecture

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 42

Report

Which of the following represents the Moore model for sequential circuits?

A

B

C

D

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 43

Report

An anti-aliasing filter is

A

An analog filter

B

A digital filter

C

Can be analog or digital

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 44

Report

Which of the following filter has the fastest roll-off ?

A

R-C

B

Bessel

C

Butterworth

D

Chebyshev

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 45

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Find the rms value of the signal $$x(t) = 5 \cos \left(50 t + \frac{\pi}{3}\right)$$

A

$$\sqrt{5}$$

B

$$\sqrt{5 \times 50 t}$$

C

$$\sqrt{50 + \frac{\pi}{3}}$$

D

$$\sqrt{12.5}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 46

Report

Determine the value indicated by a DC voltmeter for the waveform given below

A

0 V

B

2.5 V

C

10 V

D

5 V

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 47

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Evaluate the function $$\int_{0}^{\infty}t^2 \delta(t - 3)dt$$

A

$$e^{-t^2}$$

B

$$\frac{t^3}{3}$$

C

$$t^2(t - 3)$$

D

9

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 48

Report

A husband and wife appear in an interview for two vacancies for same post. The probability of husband getting selected is $$\frac{1}{5}$$ while the probability of wife getting selected is $$\frac{1}{7}$$. Then the probability that anyone of them getting selected is

A

$$\frac{11}{35}$$

B

$$\frac{12}{35}$$

C

$$\frac{1}{35}$$

D

$$\frac{34}{35}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 49

Report

The rms value of Complex waveforms are measured using

A

Transistor Voltmeter

B

Differential Voltmeter

C

High bandwidth Voltmeter

D

Voltmeter containing heat sensing elements such as thermocouples

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 50

Report

Find the fundamental Period T of the following continuous signal
$$x(t) = 20 \cos (10 \pi t) + \frac{\pi}{6}$$

A

$$\frac{\pi}{6}$$ sec

B

$$\frac{20 \times 10 \pi}{T}$$ sec

C

5 sec

D

$$\frac{1}{5}$$ sec

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 51

Report

In the circuit shown the switch closes at t=0. The voltage across 4 $$\mu F$$ capacitor in ideal condition changes to

A

0

B

16 V

C

15 V

D

24 V

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 52

Report

The 2 - part network of Fig A has open circuit impedance parameters given by matrix

A

$$\begin{bmatrix}R & R \\R & R \end{bmatrix}$$

B

$$\begin{bmatrix}R & 0 \\0 & R \end{bmatrix}$$

C

$$\begin{bmatrix}\infty & R \\R & \infty \end{bmatrix}$$

D

$$\begin{bmatrix}R & \infty \\\infty & R \end{bmatrix}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 53

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The network shown in the figure draw a current I. If the ends a and b are shorted, the current drawn would be

A

6 I

B

4 I

C

2 I

D

I

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 54

Report

As comparedto a full-waverectifier using two diodes, the four diode.bridge rectifiier has the dominant advantage of

A

higher current carrying capacity

B

lower peak inverse voltage

C

lower ripple factor

D

higher efficiency

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 55

Report

When a unit impulse voltage is applied to an inductor of 1 H, the energy supplied by the source is

A

$$\infty$$

B

$$1 J$$

C

$$\frac{1}{2} J$$

D

$$0$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 56

Report

The value of R for i = 2A is

A

5

B

10

C

40

D

60

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 57

Report

The time constant for the circuit shown below is

A

0.2 microsecond

B

0.8 millisecond

C

0.4 millisecond

D

0.2 millisecond

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 58

Report

For a sinusoidal input, the circuit shown in the figure will act as a

A

Pulse generator

B

Ramp generator

C

Full-wave rectifier

D

Voltage doubler

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 59

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A second-order band-pass activefilter can be obtained by cascading a low pass second order section having cutoff frequency $$f_{OH}$$ with a high pass second ordersection having cut-off frequency $$f_{OL}$$, provided

A

$$f_{OH} > f_{OL}$$

B

$$f_{OH} < f_{OL}$$

C

$$f_{OH} = f_{OL}$$

D

$$f_{OH} \leq \frac{1}{2} f_{OL}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 60

Report

If $$\alpha = 0.995, I_E = 10 mA$$ and $$I_{CO} = 0.5 \mu A$$, then $$I_{CEO}$$ will be

A

$$100 \mu A$$

B

$$10.1 mA$$

C

$$25 \mu A$$

D

$$10.5 mA$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 61

Report

A programme having features suchas data abstraction, encapsulation and data hiding, polymorphism inheritance is called

A

Structured programme

B

Object oriented programme

C

Open source programme

D

Real time programme

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 62

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The library function exit () causes as exit from

A

the loop in which it occurs

B

the block is which it occurs

C

the functions in which it occurs

D

the programmein which it occurs

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 63

Report

The “go to statement” causes control to go to

A

An operator

B

A label

C

A variable

D

A function

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 64

Report

The differential equation satisfying $$y = A + e^{3x} + B e^{2x}$$ is

A

$$\frac{d^2y}{dx^2} + 5 \frac{dy}{dx} - 6y = 0$$

B

$$\frac{d^2y}{dx^2} - 5 \frac{dy}{dx} + 6y = 0$$

C

$$\frac{d^2y}{dx^2} + 5 \frac{dy}{dx} + 6y = 0$$

D

$$\frac{d^2y}{dx^2} - 5 \frac{dy}{dx} - 6y = 0$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 65

Report

Foran energy signalg(t) andits time-shifted version f(t - T),the

A

amplitude spectra are identical and their phase spectra are also identical

B

amplitude spectra are identical but their phase spectra are different

C

amplitude spectra are different but their phase spectra are identical

D

amplitude spectra and their"phase spectra are different

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 66

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As the modulation index of an FM signal with sinusoidal modulation is increased from zero) to two, the powerin the carrier component will

A

Decrease continuously

B

Increase continuously

C

First increase, becomes zero and then decrease

D

First decrease, become zero and then increase

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 67

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For a short wave radio link between two stations via the ionosphere, the ratio of the maximum usable frequencyto the critical frequency

A

is always less than 1

B

May be $$\leq 1$$ depending on the distance between the two stations

C

is always greater than 1

D

Does not depend on the distance between the two stations

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 68

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A carrier voltageis simultaneously modulated by two sine waves causing modulation indices of 0.4 and 0.3. The overall modulation index is

A

0.35

B

0.7

C

0.5

D

Can not be calculated unless the phase relations are known

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 69

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If each stage has a gain of 10 dB, andnoise figure of 10dB, then the overall noise figure of a two-stage cascade amplifier will be

A

10

B

1.09

C

1.0

D

10.9

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 70

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De-emphasis circuit is used

A

To attenuate high frequencies

B

To attenuate low frequencies

C

To attenuate midband frequencies

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 71

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An amplifier has an input power of 2 microwatts. The powergain of the amplifier iis 60 dB. The output power will be

A

6 microwatts

B

120 microwatts

C

2 milliwat

D

2 watts

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 72

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A transmission line has a VSWR of2, the reflection coefficient is

A

$$\frac{1}{3}$$

B

0

C

$$\frac{1}{4}$$

D

$$\frac{1}{2}$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 73

Report

Which vacuum based deviceis widely used as a power amplifier in satellite communication systems?

A

Amplitron

B

Kystron

C

Magnetron

D

TWT

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 74

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Maxwell’s equations establish the relationship between $$\overline{E}, \overline{D}, \overline{H}$$ and $$\overline{B}$$ at any point in a continuous medium. When we move from one medium to another, then which of the following statement is correct

A

At the boundary separating the two media, the tangential components of $$\overline{E}$$ and $$\overline{H}$$ are continuous

B

At the boundary separating the two media, the tangential components of only $$\overline{E}$$ are continuous

C

If there are surface charges presenton the bouridary then normal component of $$\overline{D}$$ is continuous

D

If there are no surface charges then normal componentof $$\overline{D}$$ is discontinous

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 75

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The input impedance of shortcircuited lossless line of length less than a quarter-wavelenth is

A

Purely resistive

B

Purely inductive

C

Purely capacitive

D

Complex

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 76

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The intrinsic impedanceof free space is 377 Ω. The approximate intrinsic impedance of a medium with relative premittivity and permeability of 4 and 1 respectively will be

A

75 Ω

B

94 Ω

C

188 Ω

D

377 Ω

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 77

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A 8 kHz communication channel has an SNR of 30 GB.If the channel bandwidth is doubled, keeping the signal power constant, the SNRfor the modified channel will be

A

27 dB

B

30 dB

C

33 dB

D

60 dB

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 78

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Two orthogonal signals $$s_1(t)$$ and $$s_2(t)$$ satisfy the following relation

A

$$\int_{0}^{T} S_1(t)S_2(t)dt = 0$$

B

$$\int_{0}^{T} S_1(t)S_2(t)dt = 1$$

C

$$\int_{0}^{T} S_1(t)S_2(t)dt = \infty$$

D

$$\int_{0}^{T} S_1(t)S_2(t)dt = \pi$$

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 79

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In which modulation system, when modulating frequency is doubled, the modulation index also becomes double.

A

AM

B

FM

C

PM

D

None of the above

View Solution

ISRO Scientist or Engineer Electronics 2008 - Question 80

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The matrix $$A = \begin{bmatrix}-4 & -3 & -3 \\1 & 0 & 1 \\ 4 & 4 & x \end{bmatrix}$$ is its own adjoint. The value of x will be

A

5

B

3

C

-3

D

-5

View Solution