Modulation techniques (AM, FM, PM) MCQs January 8, 2026November 20, 2024 by u930973931_answers 20 min Score: 0 Attempted: 0/20 Subscribe 1. What is the purpose of modulation in communication systems? (A) To eliminate noise from the signal (B) To increase the frequency of the signal (C) To encode information onto a carrier wave for transmission (D) To amplify the transmitted signal 2. Which of the following is NOT a modulation technique? (A) Amplitude Modulation (AM) (B) Frequency Modulation (FM) (C) Analog Multiplexing (D) Pulse Modulation (PM) 3. In AM, the parameter of the carrier wave that is varied is: (A) Frequency (B) Amplitude (C) Phase (D) Wavelength 4. Which of the following is an application of AM? (A) AM radio broadcasting (B) Satellite communication (C) Wi-Fi communication (D) Mobile telephony 5. What is the bandwidth requirement for an AM signal with a maximum modulating frequency of 5 kHz? (A) 10 kHz (B) 5 kHz (C) 15 kHz (D) 20 kHz 6. Which term refers to the ratio of the amplitude of the modulating signal to the amplitude of the carrier signal? (A) Modulation index (B) Modulation depth (C) Signal-to-noise ratio (D) Bandwidth efficiency 7. In FM, the parameter of the carrier wave that is varied is: (A) Frequency (B) Amplitude (C) Phase (D) Wavelength 8. Which of the following is a primary advantage of FM over AM? (A) Better noise immunity (B) Lower bandwidth requirement (C) Simpler demodulation (D) Higher transmission power 9. What determines the bandwidth of an FM signal? (A) The amplitude of the carrier wave (B) The modulating signal frequency and amplitude (C) The phase of the carrier wave (D) The carrier frequency 10. FM is widely used in which of the following applications? (A) AM radio broadcasting (B) High-fidelity music transmission (C) Morse code transmission (D) Radar systems 11. In PM, the parameter of the carrier wave that is varied is: (A) Frequency (B) Phase (C) Amplitude (D) Wavelength 12. Phase modulation is closely related to which other modulation technique? (A) AM (B) PCM (C) FM (D) QAM 13. Which of the following is an application of phase modulation (PM)? (A) Optical fiber communication (B) GSM cellular communication (C) Morse code transmission (D) AM radio 14. Which modulation technique requires the largest bandwidth? (A) AM (B) PM (C) FM (D) All require the same bandwidth 15. Which modulation technique is least affected by noise? (A) FM (B) AM (C) PM (D) All are equally affected 16. In terms of complexity, which modulation scheme is the simplest to implement? (A) AM (B) FM (C) PM (D) All are equally complex 17. The process of recovering the original information signal from a modulated carrier is called: (A) Encoding (B) Multiplexing (C) Demodulation (D) Modulation 18. What is the modulation index for FM if the maximum frequency deviation is 50 kHz and the modulating frequency is 5 kHz? (A) 5 (B) 10 (C) 50 (D) 500 19. In AM, the total power transmitted is split between the carrier and: (A) Sidebands (B) Noise (C) Phase variation (D) Harmonics 20. FM signals are demodulated using: (A) Both B and C (B) Frequency discriminators (C) Phase-locked loops (PLL) (D) Envelope detectors