Analog Communications Questions and Answers – FM Receiver

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This set of Analog Communications Multiple Choice Questions & Answers (MCQs) focuses on “FM Receiver”.

1. What is the auto-correlation function of a signal (t) at t0=0?
a) It is equal to average voltage of the signal
b) It is equal to average power of the signal
c) It is equal to zero
d) It is equal to infinite
View Answer

Answer: b
Explanation: Auto-correlation function is also known as serial-correlation. It is the correlation of a function with a delayed copy of itself. So it is non-unique description of signals. For a signal (t) at t0=0, it is equal to the average power of the signal.
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2. The auto-correlation function is _________
a) impulse function
b) linear function
c) odd function
d) even function
View Answer

Answer: d
Explanation: Auto-correlation is an even function. Sometimes it is also known as serial-correlation. It is the correlation of a function with a delayed copy of itself.

3. A signal is called ergodic if all type of ensemble averages are constant.
a) True
b) False
View Answer

Answer: b
Explanation: A random signal is ergodic if time averages equals ensemble averages. Thus, if all type of ensemble averages can be interchanged.
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4. A ransom signal is defined as ergodic, if ________
a) all type of ensemble averages are interchangeable
b) all type of ensemble averages are not interchangeable
c) all type of ensemble averages are constant
d) all type of ensemble averages are double than their previous value
View Answer

Answer: a
Explanation: A stochastic process is said to be ergodic if its properties can be reduced from a single. A non ergodic process changes erratically at an inconsistent rate. Ergodic process exists if many random signals have identical time and ensemble averages. Thus, if all type of ensemble averages can be interchanged.

5. Which statement is correct about ergodic process?
a) ensemble and time averages are different
b) ensemble and time averages are opposite to each other
c) ensemble and time averages are identical
d) ensemble average are exactly twice of time averages
View Answer

Answer: c
Explanation: A stochastic process is said to be ergodic if its properties can be reduced from a single. A non ergodic process changes erratically at an inconsistent rate. Ergodic process exists if many random signals have identical time and ensemble averages.
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6. Communication consists of electrical means of sending information only.
a) True
b) False
View Answer

Answer: b
Explanation: Communication consists of means of sending, receiving and processing information via electromagnetic waves.

7. In communication system, redundancy ________
a) Helps to detect error
b) Helps to correct error
c) Reduces efficiency of communication
d) Helps to detect and correct error and also reduces efficiency
View Answer

Answer: d
Explanation: Redundancy helps in many ways in communication. It not only helps to detect an error but also helps in correcting it. It sometimes reduces efficiency also. It is basically the duplication or can say that it is the backup of some important components, so as to efficiently detect the code, with the intention of increasing reliability of the system.
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8. Which statement is true about emitter modulator amplifier for amplitude modulation?
a) operates in class A mode
b) operates in class C mode
c) operates in class B mode
d) operates in class D mode
View Answer

Answer: a
Explanation: Emitter modulator amplifier for AM operates in class A mode and also has very low efficiency. The output of this modulator is very small and therefore it is not suitable for modulation at a high level.

Sanfoundry Global Education & Learning Series – Analog Communications.

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To practice all areas of Analog Communications, here is complete set of 1000+ Multiple Choice Questions and Answers.

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Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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