11. In PCM, the parameter varied in accordance with the amplitude of the modulating signal is

- Frequency
- Phase
- Amplitude
- None of the above

12. The error probability of a PCM is

- Gaussian noise + error component due to inter symbol interference
- Calculated using power spectral density
- Calculated using noise and inter symbol interference
- All of the above

13. In Delta Modulation, the bit rate is

- N times the modulating frequency
- N times the nyquist criteria
- N times the sampling frequency
- None of the above

14. DPCM is a technique

- Where difference between successive samples of the analog signals are encoded into n-bit data streams
- Where digital codes are the quantized values of the predicted value
- To convert analog signal into digital signal
- All of the above

15. Granular noise occurs when

- Step size is too large
- There is interference from the adjacent channel
- Step size is too small
- Bandwidth is too large

16. The digital modulation technique in which the step size is varied according to the variation in the slope of the input is called

- PCM
- Adaptive delta modulation
- Delta modulation
- PAM

17. In Adaptive Delta Modulation, the slope error reduces and

- Quantization error increases
- Quantization error remains same
- Quantization error decreases
- None of the above

18. Matched filters may be used

- In parameter estimation problems
- To estimate the distance of the object
- To estimate the frequency of the received signal
- All of the above

19. Information rate is defined as

- Average number of bits of information per second
- rH
- Information per unit time
- All of the above

20. Entropy is

- Information in a signal
- Amplitude of signal
- Average information per message
- All of the above

MCQ Multiple Choice Questions and Answers on Digital Communication

Digital Communication Question and Answer