Pulse Modulation MCQ

16. Good voice reproduction via PCM requires 128 quantization levels. If bandwidth of voice channel is 4 kHz, then data rate is

  1. 128 kbps
  2. 250 kbps
  3. 28 kbps
  4. 56 kbps
Answer
Answer. d

17. In high-speed TDM, the channels are separated in the receiver employing

  1. OR gate
  2. NAND gate
  3. NOR gate
  4. AND gate
Answer
Answer. d

18. PPM signal is

  1. Differentiation of PWM
  2. Integration of PWM
  3. Differentiation of PAM
  4. Not related to PWM or PAM
Answer
Answer. a

19. In differential PCM, each word indicates

  1. Difference between a sample amplitude and a reference signal
  2. Difference in amplitude between a sample and the previous sample
  3. Addition of a sample amplitude and a reference signal
  4. Addition of amplitude of a sample and the previous sample
Answer
Answer. b

20. The demodulation of a delta modulated signal is achieved by

  1. Differentiation
  2. Integration
  3. Band-pass filtering
  4. Sampling
Answer
Answer. b

21. Quantizing noise occurs in

  1. Pulse width modulation
  2. Frequency division multiplexing
  3. Pulse code modulation
  4. Time-division multiplexing
Answer
Answer. c

22. For which of the following system, the signal to noise ratio is the highest?

  1. PAM
  2. PWM
  3. PAM and PWM
  4. PPM
Answer
Answer. d

23. A 3000 Hz bandwidth channel has a capacity of 30 kbps. The signal-to-noise ratio of the channel is

  1. 25 dB
  2. 20 dB
  3. 40 dB
  4. 30 dB
Answer
Answer. d

24. The most noise immune system is

  1. SSB
  2. PCM
  3. PDM
  4. PWM
Answer
Answer. b

25. Which one of the following pulse communications systems is digital?

  1. PAM
  2. PCM
  3. PPM
  4. PWM
Answer
Answer. b

26. For a non-uniform quantizer more quantizing steps are used for signals of

  1. Low frequency
  2. High amplitude
  3. Low amplitude
  4. High frequency
Answer
Answer. b

27. Which one of the following is a disadvantage of digital transmission as compared to analog transmission?

  1. Digital signals cannot be multiplexed efficiently
  2. Digital transmission is less immune to channel noise
  3. Digital signals need to be coded before transmission
  4. Digital transmission needs more bandwidth
Answer
Answer. d

28. What are the three steps in generating PCM in the correct sequence?

  1. Sampling, quantizing and encoding
  2. Encoding, sampling and quantizing
  3. Sampling, encoding and quantizing
  4. Quantizing, sampling and encoding
Answer
Answer. a

29. Which one of the following is the correct statement?

Time-division multiplexing

  1. stacks several channels in adjacent frequency slots
  2. interleaves pulses belonging to different transmissions
  3. combines groups into a single super group
  4. can be used with PCM only
Answer
Answer. b

30. Voice is digitized using an ADC with a sampling period of 0-1 millisecond and 10 bits/sample. What is the bit rate in kbps generated by this system?

  1. 100 kbps
  2. 1000 kbps
  3. 9.9 kbps
  4. 10.1 kbps
Answer
Answer. a
Pages: 1 2 3