This set of Digital Communications Multiple Choice Questions & Answers (MCQs) focuses on “Types of Processes”.

1. A stationary stochastic process has

a) Finite energy signal

b) Infinite zero signal

c) Zero energy signal

d) None of the mentioned

View Answer

Explanation: A stationary stochastic process is an infinite energy signal and hence its fourier transform does not exist.

2. The power spectral density function of the stochastic process is

a) Real

b) Odd

c) Real & odd

d) None of the mentioned

View Answer

Explanation: The power spectral density function of a stochastic function is real and even.

3. For a periodic function, the spectral density and auto correlation functions form

a) Fourier transform pair

b) Laplace transform pair

c) Hilbert transform pair

d) Z transform pair

View Answer

Explanation: For a periodic function, the spectral density and auto correlation function forms fourier transform pair.

4. The capacity of a channel is given by

a) Number of digits used in coding

b) Volume of information it can take

c) Maximum rate of information transmitted

d) Bandwidth requires information

View Answer

Explanation: The capacity of the channel is given by a maximum rate of information transmitted.

5. In a communication system, a process in which statistical averages and time averages are equal is called as

a) Stationary

b) Ergodic

c) Gaussian

d) Poisson

View Answer

Explanation: In ergodic process statistical averages and time averages are equal.

6. A rectangular pulse of duration T is applied to a matched filter. The output of the filter is a

a) Rectangular pulse of duration T

b) Rectangular pulse of duration 2T

c) Triangular pulse

d) Sine function

View Answer

Explanation: The output of the matched filter when a rectangular pulse of duration T is applied is a triangular pulse.

7. The line code has a zero dc component for pulse transmission of random binary data is

a) NRZ

b) RZ

c) Alternate mark inversion

d) None of the mentioned

View Answer

Explanation: The line code has a zero dc component for pulse transmission of random binary data is alternate mark inversion.

8. The auto-correlation of white noise is

a) A delta function

b) A constant

c) Gaussian

d) None of the mentioned

View Answer

Explanation: The auto-correlation of white noise is a delta function.

9. Ionospheric communication can take place in

a) High frequency band

b) Very high frequency band

c) Ultra high frequency band

d) Super high frequency band

View Answer

Explanation: Ionospheric communication takes place in high frequency band.

10. Satellite communication takes place in

a) Ultra high frequency band

b) Super high frequency band

c) Ultra & Super high frequency band

d) None of the mentioned

View Answer

Explanation: Satellite communication takes place in ultra high and super high frequency bands.

11. The weighing matrix is

a) Positive quantity

b) Inverse of covariance matrix of the input vector

c) Positive quantity & Inverse of a covariance matrix of the input vector

d) None of the mentioned

View Answer

Explanation: W is a positive definite weighing matrix and it is inverse of covariance matrix of the input vector.

12. Non uniform tree _____ bit rate.

a) Increases

b) Decreases

c) Does not affect

d) None of the mentioned

View Answer

Explanation: Non uniform tree for binary search increases the bit rate.

13. Two clock with rates T1 and T2 are incommensurate if its ratio is

a) Rational

b) Irrational

c) Equal

d) None of the mentioned

View Answer

Explanation: Two clock with rates T1 and T2 are incommensurate if its ratio is irrational.

14. Possible timing error detection methods are

a) Early late

b) Zero crossing

c) Early late & Zero crossing

d) None of the mentioned

View Answer

Explanation: Methods for timing error detections are early late timing error detection and zero crossing timing error detection method.

15. Which has minimum power loss during transmission?

a) Twisted Copper cable at 1KHz

b) Optical fiber

c) Twisted copper cable at 100KHz

d) Wave guide

View Answer

Explanation: Twisted copper wire at 1KHz have low power loss.

16. Voltage generated by lightning is an example for

a) Energy signal

b) Power signal

c) Energy & Power signal

d) None of the mentioned

View Answer

Explanation: Voltage generated by lightning is an example for energy signal and it has very high power.

**Sanfoundry Global Education & Learning Series – Digital Communications.**

To practice all areas of Digital Communications, __here is complete set of 1000+ Multiple Choice Questions and Answers__.