Top 150+ Solved Communication Skill MCQ Questions Answer
Q. The disadvantage of FM over AM is that
a. high output power is needed
b. high modulating power is needed
c. noise is very high for high frequency
d. large bandwidth is required
Q. Which of the following is used to generate PDM?
a. free running multi-vibrator
b. monostable multi-vibrator
c. jk flip-flop
d. schmitt trigger
Q. SSB can be generated by
a. filter method
b. phase cancellation method
c. good attenuation characteristics
d. all of the above
Q. A zero mean white Gaussian noise is passed through an ideal low pass filter of bandwidth 10 kHz. The output of the samples so obtained would be
a. correlated
b. statistically independent
c. uncorrelated
d. orthogonal
Q. What is the purpose of peak clipper circuits in radio transmitters?
a. to prevent overmodulation
b. to reduce bandwidth
c. to increase bandwidth
d. to regulate oscillator i/p voltage
Q. In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
a. class c amplifiers
b. linear devices
c. non-linear devices
d. harmonic devices
Q. Under ordinary circumstances, impulse noise can be reduced in
a. fm only
b. am only
c. both am and fm
d. none of the above
Q. In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
a. amplitude of distant sidebands decreases
b. amplitude of distant sidebands increases
c. amplitude of distant sidebands remains constant
d. amplitude of distant sidebands first increases, then decreases
Q. If sampling is done at the rate of 10 kHz. The bandwidth required is
a. 35 khz
b. 70 khz
c. 10 khz
d. 1280 khz
Q. It is found that a ship to ship communication suffers from fading. This can be avoided by using
a. space diversity
b. frequency diversity
c. broad band antenna
d. directional antenna
Q. In practical commercial FM system, channel bandwidth is
a. 150 khz
b. 100 khz
c. 88 mhz
d. 108 mhz
Q. In EM waves, polarization
a. is always vertical in an isotropic medium
b. is caused by reflection
c. is due to transverse nature of waves
d. results from longitudinal nature of waves
Q. The maximum power output of a standard A earth station over the total band allocated to satellite communication is about
a. 0.5 kw
b. 8 kw
c. 20 kw
d. 50 kw
Q. PAM stands for
a. pulse analogue modulation
b. phase analogue modulation
c. pulse amplitude modulation
d. phase amplitude modulation