Analog Communications Multiple Choice Questions focuses on “Advantages of Filter Method”.
1. Which of the following does not cause losses in optical fibre cables?
a) Stepped index operation
b) Scattering
c) Microbending
d) Light absorption
Answer: a
Clarification: In Stepped index operation, refractive index within the core is uniform. There is also a sharp decrease in refractive index at the core-cladding interface. It generally does not cause any type os losses in optical fibre cables.
2. In televisions, equalizing pulses are sent during __________
a) horizontal blanking
b) vertical blanking
c) serrations
d) horizontal retrace
Answer: a
Clarification: The duration of an equalizing pulse is approximately 2.5 microseconds. The repetition frequency of equalizing pulses is twice the line frequency. It is necessary to sent equalizing pulses during horizontal blanking in televisions.
3. It is generally observed that a ship to ship communication suffers from fading. This problem can be avoided by using ________
a) space diversity
b) frequency diversity
c) directional antenna
d) filter
Answer: b
Clarification: It is generally observed that a ship to ship communication suffers from fading. This problem can be avoided by using frequency diversity in which the components of a radio wave are received from different channels thus reducing the error that occurs in the transmission of a single frequency component.
4. What is the characteristic impedance of a twin wire feeder used in television?
a) 1000 ohm
b) 100 ohm
c) 10 ohm
d) 300 ohm
Answer: d
Clarification: Twin wire feeder consists of two wires with spacers. For a twin wire feeder the characteristic impedance should be close to 300 ohm.
5. A buffer amplifier is a cathode follower double tuned amplifier.
a) True
b) False
Answer: b
Clarification: Gain of an amplifier is it’s ability to increase the voltage at the input and produce the result at the output. A buffer amplifier is basically a high gain DC amplifier. It is basically used for transferring voltage from a high output impedance level to a low input impedance level circuit.
6. What is the direction of rotation of a CD?
a) anticlockwise
b) clockwise
c) either clockwise or anticlockwise depend on data stored
d) first anticlockwise and then clockwise
Answer: a
Clarification: CD stands for compact disk. The direction of rotation of Compact Disk is anticlockwise.
7. According to Fourier Analysis a square wave can be represented as a fundamental sine wave and even harmonics.
a) True
b) False
Answer: b
Clarification: A square wave is a periodic non-sinusoidal waveform with an uniform frequency, in which the amplitude alternates between a fixed maximum and minimum value. According to Fourier analysis, a square wave can be represented as an infinite sum of sinusoidal waves. A square wave consists of only components of odd integer harmonics.
8. Filter method is the one and only method to produce SSB.
a) True
b) False
Answer: b
Clarification: SSB can be produced by filter method also known as frequency discrimination method. It can also be produced by phase discrimination method.
9. Impulse noise can be reduced in _________
a) FM
b) AM
c) QAM
d) PM
Answer: a
Clarification: Impulse noise includes unwanted, almost instantaneous sharp sounds. It is only in frequency modulated circuits that allow reduction in impulse noise.
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