Analog and Digital Communication Systems MCQs January 8, 2026July 11, 2024 by u930973931_answers 20 min Score: 0 Attempted: 0/20 Subscribe 1. Which of the following is not a characteristic of analog communication? (A) Susceptible to noise (B) Infinite resolution (C) High noise immunity (D) Continuous signal representation 2. In analog communication, the signal is typically represented by: (A) Discrete values (B) Digital pulses (C) Binary digits (D) Continuous waveforms 3. The process of converting analog signals into digital form is known as: (A) Modulation (B) Demodulation (C) Sampling (D) Quantization 4. The bandwidth of an FM signal: (A) Depends on the frequency deviation and modulation index (B) Is independent of modulation index (C) Is only affected by frequency deviation (D) Is zero for pure sine wave modulation 5. Which modulation technique is used for transmitting digital data over analog channels? (A) Quadrature Amplitude Modulation (QAM) (B) Frequency Modulation (FM) (C) Phase Modulation (PM) (D) Amplitude Modulation (AM) 6. PCM stands for: (A) Pulse Code Modulation (B) Phase Code Modulation (C) Phase Continuous Modulation (D) Pulse Continuous Modulation 7. In PCM, quantization noise can be reduced by: (A) Increasing the sampling rate (B) Decreasing the number of quantization levels (C) Using a larger number of quantization levels (D) Increasing the amplitude of the signal 8. The Nyquist sampling theorem states that: (A) Sampling rate should be more than half the highest frequency component (B) Sampling rate should be less than half the highest frequency component (C) Sampling rate should be equal to the highest frequency component (D) There is no relationship between sampling rate and frequency component 9. Which of the following is an advantage of digital communication over analog communication? (A) Lower security (B) Higher bandwidth efficiency (C) More susceptible to noise (D) Limited dynamic range 10. The process of converting digital signals back into analog form is called: (A) Demodulation (B) Modulation (C) Sampling (D) D/A conversion 11. Which of the following is used to combine baseband signals for transmission over a common medium? (A) Demodulator (B) Multiplexer (C) Modulator (D) Oscillator 12. Which modulation technique is widely used in broadcast radio transmission? (A) QAM (B) FM (C) AM (D) PCM 13. Which of the following is not a type of digital modulation? (A) AM (Amplitude Modulation) (B) FSK (Frequency Shift Keying) (C) PSK (Phase Shift Keying) (D) QAM (Quadrature Amplitude Modulation) 14. In digital communication, FEC (Forward Error Correction) is used to: (A) Detect errors and request retransmission (B) Prevent errors during transmission (C) Correct errors without the need for retransmission (D) Reduce bandwidth requirements 15. A signal is sampled at a rate of 8 kHz. What is the Nyquist frequency for this signal? (A) 16 kHz (B) 8 kHz (C) 4 kHz (D) 32 kHz 16. Which of the following is a disadvantage of analog communication? (A) Limited repeatability (B) More immune to electromagnetic interference (C) Higher fidelity (D) Easier synchronization 17. The process of converting digital data into digital signals is known as: (A) Modulation (B) Digital-to-Analog Conversion (C) Demodulation (D) Analog-to-Digital Conversion 18. In digital communication, what does BER stand for? (A) Bandwidth Error Rate (B) Bit Error Rate (C) Binary Error Rate (D) Burst Error Rate 19. In a PCM system with 8-bit quantization, the number of possible quantization levels is: (A) 512 (B) 128 (C) 64 (D) 256 20. Which of the following is a key characteristic of QAM? (A) It uses multiple carriers (B) It is only used for analog modulation (C) It uses phase modulation (D) It has low spectral efficiency