BSNL TTA Communication MCQ Part One

BSNL TTA Communication MCQ Part One

NOTE.NO OF QUESTIONS-100 QUESTIONS
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 QUESTIONS AND ANSWER

1) Radiation resistance of an antenna is a
A [ ]) dc resistance
B [v]) ac resistance
C [ ]) either (a) or (b)
D [ ]) none of the above

2) The input to a coherent detector is DSB – SC signal plus noise. The noise at the detector output is
A [v]) in phase component
B [ ]) quadrature component
C [ ]) zero
D [ ]) the envelope

3) All of the output pulses are at full transmitter power for a strong signal in all of the following except
A [ ]) PWM
B [v]) PAM
C [ ]) PFM
D [ ]) PCM

BSNL TTA Communication MCQ Part One

4) In a telephone system, the grade of service means
A [ ]) the quality of sound reception at the receiver telephone
B [v]) the probability that a called for connection is established
C [ ]) the type of wires cables used for the system
D [ ]) none of the above

5) AGC(Automatic gain control) voltage is applied to the stages which are
A [v]) before the detector stage
B [ ]) after the detector stage
C [ ]) either before or after the detector stage
D [ ]) none of the above

6) Which of the following stage is not present in AM receiver as compared to FM receiver?
A [ ]) AM amplifier
B [ ]) Demodulator
C [v]) Amplitude limiter
D [ ]) AF amplitude

7) The function of duplexer in a RADAR is
A [v]) to permit the use of same antenna for transmission and reception
B [ ]) to provide gain to the transmitted power
C [ ]) to amplify the received signal
D [ ]) both (b) and (c)

BSNL TTA Communication MCQ Part One

8) In FM, as the modulating frequency decreases and the modulating voltage amplitude
A [ ]) increases, the modulation index increases
B [ ]) decrease, the modulation index increases
C [v]) remains constant, the modulation index increases
D [ ]) remains constant, the modulation index decreases
E [ ]) HINTS-modulation index=frequency deviation /modulating frequency

9) Modulation system used for video-modulation in television broadcast is
A [ ]) SSB AM with carrier
B [ ]) SSB with carrier suppressed
C [ ]) DSB AM with carrier
D [v]) a modified form of SSB with carrier called vestigial sideband

10) The highest modulation frequencies typically used in FM broadcast is
A [ ]) 5 kHz
B [v]) 15 kHz
C [ ]) 25 kHz
D [ ]) 10 kHz

11) For a short dipole having an effective length less than half the wavelength the radiation resistance is
A [v]) proportional to length
B [ ]) proportional to square root of length
C [ ]) proportional to square of length
D [ ]) none of the above

BSNL TTA Communication MCQ Part One

12) A narrow band noise show
A [ ]) AM only
B [v]) AM and FM
C [ ]) FM
D [ ]) PCM

13) The modulation index of a narrowband FM signal is
A [v]) nearly equal to 0.3
B [ ]) much less than unity
C [ ]) nearly 0.5
D [ ]) much more than unity

14) Which is a digital coding technique?
A [ ]) PCM
B [ ]) DM
C [ ]) DPCM
D [v]) All

15) For the transmission of normal speech, the PCM channel needs a bandwidth of __________ kHz.
A [ ]) 2
B [v]) 4
C [ ]) 16
D [ ]) 32

BSNL TTA Communication MCQ Part One

16) Neper is
A [v]) larger than a decibel
B [ ]) smaller than decibel
C [ ]) equal to 1 decibel
D [ ]) none of the above

17) Which of following digital modulation technique?
A [ ]) ASK
B [ ]) FSK
C [ ]) PSK
D [v]) All

18) The standard intermediate frequency for FM ratio is
A [v]) 10.7 MHz
B [ ]) 4.5 MHz
C [ ]) 75 kHz
D [ ]) 455 kHz

19) In an end fire array, the radiation pattern
A [v]) is in the plane of array
B [ ]) is at right angles to array
C [ ]) is at an angle to the plane of array
D [ ]) either (b) or (c)

20) Armstrong FM transmitter uses
A [ ]) LC oscillator
B [v]) crystal oscillator
C [ ]) RC oscillator
D [ ]) either (a) or (c)

BSNL TTA Communication MCQ Part One