This set of Analog Communications test focuses on “Bandwidth of FM Signal with Arbitrary m(t)”.
1. When two or more signals share a common channel, it is called ________
Explanation: Multiplexing is a method by which multiple analog or digital signals are combined. In multiplexing many signals are combined into one signal over a shared medium.
2. One of the reason of distortion is shift in phase relationships between baseband frequencies.
Explanation: If we shift the phase relationships between baseband frequencies, it will ultimately results in distortion.
3. Miller effect can cause an amplifier to oscillate.
Explanation: Miller effect is responsible for the increase in equivalent input capacitance of an inverting voltage amplifier. The increase equivalent input capacitance is given by, CM = C(1 + AV).
4. How can we successfully avoid Miller effect?
a) using a common-base amplifier
b) using a common-emitter amplifier
c) by increasing the Q factor
d) by decreasing the Q factor
Explanation: Miller effect is responsible for the increase in equivalent input capacitance of an inverting voltage amplifier. The increase equivalent input capacitance is given by, CM = C(1 + AV). Miller effect can be avoided by using a common-base amplifier.
5. What is the two basic specification of a receiver?
a) sensitivity and selectivity
b) superious response and tracking
c) signal and noise
d) number of convertors and number of IFs
Explanation: Sensitivity and selectivity are the two key specifications for any receiver, which is used for the purpose in communication.
6. Who invented the superheterodyne receivers?
Explanation: Superheterodyne uses frequency mixing to convert a received signal to a fixed IF. This IF can be processed more easily than the original carrier frequency. IT was invented by Armstrong.
7. Skin effect refers ________
a) the increase of wire resistance with frequency
b) the decrease of wire resistance with frequency
c) the uniform nature of wire resistance with frequency
d) the way radio signals travel across a flat surface
Explanation: Skin effect becomes more and more apparent as frequency increases. It refers to the increase of wire resistance with frequency.
8. What is the full form of AFC?
a) Amplitude to frequency conversion
b) Automatic frequency conversion
c) Automatic frequency control
d) Audio frequency control
Explanation: AFC stands for Automatic frequency control. It is a method to automatically keep a resonant circuit tuned to frequency of an incoming radio signal.
9. The frequency of local oscillator ________
a) is above the RF frequency
b) is below the RF frequency
c) can be either below or above the RF frequency
d) is fixed typically at 450KHz
Explanation: The frequency of local oscillator is not fixed. It can be below or above the RF frequency.
10. Phase distortion is important in ________
a) voice communication systems
b) color video receivers
c) monochrome video receivers
d) radio reception
Explanation: Phase distortion is change in the shape of waveform. It occurs when filter’s phase response is not linear over the frequency range of interest. It is important in color video receivers.
Sanfoundry Global Education & Learning Series – Analog Communications.
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