Communication Systems – Multiple Choice Questions (MCQs)

1. 13. What is the primary advantage of digital communication over analog communication?

   • A. Less bandwidth
   • B. More robust to noise
   • C. Lower cost
   • D. Simpler hardware

2. 14. The Nyquist rate for sampling a continuous-time signal x(t) with maximum frequency fm is:

   • A. fm
   • B. 2fm
   • C. fm/2
   • D. 4fm

3. 15. Quantization error occurs during the ________ step of PCM.

   • A. Sampling
   • B. Quantization
   • C. Encoding
   • D. Decoding

4. 16. The process of assigning a unique binary code to each quantized level is called:

   • A. Sampling
   • B. Quantization
   • C. Encoding
   • D. Decoding

5. 17. Differential Pulse Code Modulation (DPCM) transmits the ________ of the current sample from the previous sample.

   • A. Absolute value
   • B. Difference
   • C. Sum
   • D. Product

6. 18. Delta Modulation (DM) is a simplified form of DPCM that uses how many bits per sample?

   • A. 1
   • B. 2
   • C. 4
   • D. 8

7. 19. Which digital modulation technique varies the amplitude of the carrier wave?

   • A. ASK
   • B. FSK
   • C. PSK
   • D. QAM

8. 20. In FSK

   • A. the information is contained in the ________ of the carrier.
   • B. Amplitude
   • C. Frequency
   • D. Phase

9. 21. PSK (Phase Shift Keying) varies the ________ of the carrier based on the data.

   • A. Amplitude
   • B. Frequency
   • C. Phase
   • D. Both amplitude and phase

10. 22. QPSK (Quadrature Phase Shift Keying) transmits how many bits per symbol?

    • A. 1
    • B. 2
    • C. 4
    • D. 8

11. 23. QAM (Quadrature Amplitude Modulation) combines the features of:

    • A. ASK and FSK
    • B. ASK and PSK
    • C. FSK and PSK
    • D. None of the above

12. 24. Which type of multiplexing combines signals from multiple sources based on different time slots?

    • A. FDM
    • B. TDM
    • C. WDM
    • D. CDM