This set of Analog Communications online quiz focuses on “Noise for SSB-SC”.
1. The IF bandwidth of a radar receiver is inversely proportional to the __________
a) pulse repetition frequency
b) pulse width
c) pulse interval
d) square root of peak transmitted power
Explanation: The IF bandwidth of a radar receiver is inversely proportional to the pulse width.
2. Frequency components of an AM wave are?
a) Carrier frequency (ωc) with amplitude A
b) Lower side band (ωc + ωm) having amplitude mA⁄4
c) Upper side band (ωc – ωm) having amplitude mA⁄4
d) Carrier frequency (ωc) with amplitude A⁄2
Explanation: Actually the frequency components of AM waves are – Carrier frequency (ωc) with amplitude A, Lower side band (ωc – ωm) having amplitude mA⁄2 and Upper side band (ωc + ωm) having amplitude mA⁄2 (where m represents modulation index).
3. Which of the following statement is true, if a return echo arrives after the allocated pulse interval?
a) it will interfere with the operation of transmitter
b) the receiver might be overloaded
c) it will not be received
d) target will appear closer than it really is
Explanation: If a return echo arrives after the allocated pulse interval then the target will always appear closer than it really is.
4. Which of the following statement is true about spectrum of frequency modulated wave?
a) carrier frequency starts decreasing at a faster rate when the modulation index is large
b) the amplitude of any sideband is totally depends on modulation index
c) total number of sidebands is completely depend on the modulation index
d) carrier frequency can’t be disappear
Explanation: In frequency modulation, frequency of wave is modulated with respect to the wave being propagated. In frequency modulation, the amplitude of any side band depends on modulation index.
5. If a FM signal has modulation index m, then what will be its modulation index after passing through frequency tripler?
Explanation: Frequency multiplier is an electronic circuit that generates an output signal whose output frequency is a multiple of its input frequency. So after passing through frequency tripler, new modulation index will be 3m.
6. A pre emphasis circuit provides extra noise immunity by __________
a) boosting the base frequencies
b) amplifying the higher audio frequencies
c) preamplifying the whole audio band
d) converting the phase modulation to FM
Explanation: Pre emphasis is used to improve quality of signal at the output of data transmission. A pre emphasis circuit provides extra noise immunity noise amplifying the higher audio frequencies.
7. Which one of the following is not an advantage of FM over AM?
a) Better noise immunity is provided
b) Lower bandwidth is required
c) Transmitting power is useful
d) Less modulating power is required
Explanation: Frequency Modulation has many advantages over amplitude modulation such as it has better noise immune, it requires less modulating power. But it requires lower bandwidth is not an advantage of FM when compared to AM.
8. Which of the following statement about Amplitude Limiter is not true?
a) The circuit is always biased in class C amplifier
b) When the input increases and becomes greater than threshold of limiting, the gain starts decreasing
c) The output must be tuned
d) Leak-type bias must be used
Explanation: Amplitude Limiter removes the amplitude of output signals to a desired margin irrespective of variations in the input signal. It is always biased in class C amplifier by virtue of the leak-type bias.
9. The typical squelch circuit cuts off __________
a) An audio amplifier when the carrier is absent
b) RF interference when the signal is weak
c) An IF amplifier when AGC is maximum
d) An IF amplifier when AGC is minimum
Explanation: The use of squelch circuit is to suppress the audio or video output of a receiver in the absence of a sufficiently strong desired input signal.
10. What do you understand by high level AM?
a) Output power is low
b) Modulation is done at high power of carrier and modulating signal
c) No need to boost the carrier and modulating signal
d) Modulation is done at low power of carrier and modulating signal
Explanation: For a high level AM, modulation is done at high power of carrier and modulating signal so power amplifier is used to boost the carrier and modulating signal.
Sanfoundry Global Education & Learning Series – Analog Communications.
To practice all areas of Analog Communications for online Quizzes, here is complete set of 1000+ Multiple Choice Questions and Answers.