Communication Skill Set 4
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This set of Communication Skill Multiple Choice Questions & Answers (MCQs) focuses on Communication Skill Set 4
Q1 | FM transmitting and receiving equipment as compared to AM equipment is
- costly
- cheaper
- almost equally costly
- none of the above
Q2 | An audio signal (say from 50 Hz to 10000 Hz) is frequency translated by a carrier having a frequency of 106 Hz. The values of initial (without frequency translation) and final (after frequency translation) fractional change in frequency from one band edge to the other are
- 200 and 1.01
- 200 and 10.01
- 200 and 100.1
- 200 and 200
Q3 | If in a broadcasting studio, a 1000 kHz carrier is modulated by an audio signal of frequency range 100-5000 kHz, the width of channel is __________ kHz.
- 5
- 4.9
- 995
- 10
Q4 | Which one of the following is analog?
- pcm
- pwm
- delta modulation
- differential pcm
Q5 | The disadvantage of FM over AM is that
- high output power is needed
- high modulating power is needed
- noise is very high for high frequency
- large bandwidth is required
Q6 | Which of the following is a digital modulation technique?
- pcm
- psk
- dm
- all
Q7 | Which of the following is used to generate PDM?
- free running multi-vibrator
- monostable multi-vibrator
- jk flip-flop
- schmitt trigger
Q8 | SSB can be generated by
- filter method
- phase cancellation method
- good attenuation characteristics
- all of the above
Q9 | 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
- correlated
- statistically independent
- uncorrelated
- orthogonal
Q10 | What is the purpose of peak clipper circuits in radio transmitters?
- to prevent overmodulation
- to reduce bandwidth
- to increase bandwidth
- to regulate oscillator i/p voltage
Q11 | In case of low level amplitude modulation system, the amplifiers following the modulated stage must be
- class c amplifiers
- linear devices
- non-linear devices
- harmonic devices
Q12 | Under ordinary circumstances, impulse noise can be reduced in
- fm only
- am only
- both am and fm
- none of the above
Q13 | In case of frequency modulation, modulating voltage remains constant if the modulating frequency is lowered, then
- amplitude of distant sidebands decreases
- amplitude of distant sidebands increases
- amplitude of distant sidebands remains constant
- amplitude of distant sidebands first increases, then decreases
Q14 | If sampling is done at the rate of 10 kHz. The bandwidth required is
- 35 khz
- 70 khz
- 10 khz
- 1280 khz
Q15 | It is found that a ship to ship communication suffers from fading. This can be avoided by using
- space diversity
- frequency diversity
- broad band antenna
- directional antenna
Q16 | In practical commercial FM system, channel bandwidth is
- 150 khz
- 100 khz
- 88 mhz
- 108 mhz
Q17 | In EM waves, polarization
- is always vertical in an isotropic medium
- is caused by reflection
- is due to transverse nature of waves
- results from longitudinal nature of waves
Q18 | The maximum power output of a standard A earth station over the total band allocated to satellite communication is about
- 0.5 kw
- 8 kw
- 20 kw
- 50 kw
Q19 | PAM stands for
- pulse analogue modulation
- phase analogue modulation
- pulse amplitude modulation
- phase amplitude modulation
Q20 | The characteristic impedance of a twin wire feeder used for TV signals is about
- 1000 ohm
- 500 ohm
- 300 ohm
- 100 ohm
Q21 | In a FM receiver, amplitude limiter
- amplifiers low frequency signals
- reduces the amplitude of signals
- eliminates any change in amplitude of received fm signals
- none of the above
Q22 | A buffer amplifier is
- a double-tuned amplifier
- a high gain d.c. amplifier
- a cathode follower stage
- none of the above
Q23 | Leak type bias is used in plate modulated class C amplifier to
- increase the bandwidth
- prevent over modulation
- prevent excessive grid current
- prevent tuned circuit damping
Q24 | The direction of rotation of a CD is
- clockwise
- anticlockwise
- clockwise or anticlockwise depending on frequency of data stored
- mostly anticlockwise but some times clockwise
Q25 | One of the advantages of base modulation over collector modulation of a transistor class C amplifier is
- improved efficiency
- better linearity
- high power output per transistor
- the lower modulating power requirement