BSNL TTA (JE) COMMUNICATION 200 EXPECTED QUESTIONS PART ONE

NOTE-NO OF QUESTIONS-100
ANSWER KEY-Correct answer is indicated by symbol (V) in options.
HINTS-In some questions options E-HINTS is indicating the hints of answer

SAMPLE QUESTION AND ANSWER
1) An AM demodulator can be implemented with a linear multiplier followed by a ________
filter.
A [v]) low-pass
B [ ]) high-pass
C [ ]) band-pass
D [ ]) band-stop
2) The intermediate frequency in a standard AM receiver is
A [ ]) 455 Hz
B [v]) 455 kHz
C [ ]) 4.55 MHz.
D [ ]) none of the above
3) In order for a light ray to propagate along a fiber-optic cable, what must the relationship
be between the angle of incidence and the critical angle?
A [v]) θi > θc
B [ ]) θi < θc
C [ ]) θi = θc
D [ ]) none of the above
4) Light may be propagated along a fiber-optic cable in which of the following modes?
A [ ]) multimode step index
B [ ]) single-mode step index
C [ ]) multimode graded index
D [v]) all of the above
5) In AM, the carrier is changed by a modulating signal. What parameter of the carrier is
changed?
A [v]) amplitude
B [ ]) frequency

C [ ]) pulse width
D [ ]) phase
6) The output spectrum of a ________ modulator includes upper-side and lower-side
frequencies and the carrier frequency.
A [ ]) balanced
B [v]) standard amplitude
C [ ]) all of these
D [ ]) none
7) Amplitude modulation is a ________ process.
A [v]) multiplication
B [ ]) division
C [ ]) sum/difference
D [ ]) none
8) Speed of data transmission in 4-G network of telecom is
A [ ]) 386 kbps – 2 mbps.
B [ ]) 2 mbps
C [ ]) 2 mbps -1 gbps.
D [v]) 100 mbps – 1 gbps.
9) The frequency range for satellite communication is
A [ ]) 1 kHz – 100 kHz
B [ ]) 100 kHz – 1 MHz
C [ ]) 10 MHz – 30 MHz
D [v]) 1 GHz – 30 GHz
10) A cordless telephone using separate frequencies for transmission in base and portable
units is known as
A [v]) duplex arrangement
B [ ]) half duplex arrangement
C [ ]) either (a) or (b)

D [ ]) neither (a) nor (b)
11) For attenuation of high frequencies we should use
A [v]) shunt capacitance
B [ ]) series capacitance
C [ ]) inductance
D [ ]) resistance
12) A modem is classified as low speed if data rate handled is
A [ ]) upto 100 bps
B [ ]) upto 250 bps
C [ ]) upto 400 bps
D [v]) upto 600 bps
13) VSB modulation is preferred in TV because
A [v]) it reduces the bandwidth requirement to half
B [ ]) it avoids phase distortion at low frequencies
C [ ]) it results in better reception
D [ ]) none of the above
14) A woofer should be fed from the input through a
A [v]) low pass filter
B [ ]) high pass filter
C [ ]) band pass filter
D [ ]) band stop filter
15) The colour subcarrier and sidebands produced by its modulation with the chrominance
signals are accommodated in the standard channel width by the process of
A [ ]) frequency adjustment
B [v]) frequency interleaving
C [ ]) frequency changing
D [ ]) frequency amalgamation

16) In FM signal with a modulation index mf is passed through a frequency tripler. The
wave in the output of the tripler will have a modulation index of
A [ ]) mf
B [v]) 3mf
C [ ]) mf/3
D [ ]) mf/9
17) In colour TV receiver, varactor diode is used for
A [ ]) detection
B [ ]) rectification
C [v]) tuning
D [ ]) both (a) and (b)
18) Energy content of atmospheric noise
A [ ]) does not depend on frequency
B [v]) decreases as frequency is increased
C [ ]) increases as frequency is increased
D [ ]) either (a) or (c) depending on the temperature
19) A 400 W carrier is amplitude modulated with m = 0.75. The total power in AM is
A [ ]) 400 W
B [v]) 512 W
C [ ]) 588 W
D [ ]) 650 W
E [ ]) HINTS- 400(1+0.75²/2)=512W
20) Non-coherently detection is not possible for
A [v]) PSK
B [ ]) ASK
C [ ]) FSK
D [ ]) both (a) and (c)

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BSNL TTA (JE) COMMUNICATION 200 EXPECTED QUESTIONS PART TWO
BSNL TTA ONLINE TEST RESULT COMPUTER WINDOWS AND DOS 1

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