MCQs in Communications

(Last Updated On: December 8, 2017)

MCQs for Communications

This is the Multiple Choice Questions in Communications from the book Electronic Devices – Electron Flow Version and Conventional Current Version 8th Edition by Thomas L. Floyd. If you are looking for a reviewer in Electronics Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

Practice Exam Test Questions

Choose the letter of the best answer in each questions.

1. In AM, the carrier is changed by a modulating signal. What parameter of the carrier is changed?

  • A. amplitude
  • B. frequency
  • C. pulse width
  • D. phase

2. The intermediate frequency in a standard AM receiver is

  • A. 455 Hz.
  • B. 455 kHz.
  • C. 4.55 MHz.
  • D. none of the above

3. If a 1 MHz carrier is amplitude modulated with a 5 kHz audio signal, the upper-side frequency is _____ kHz.

  • A. 1005
  • B. 1000
  • C. 995
  • D. none of the above

4. For a four-quadrant linear multiplier, what is the output voltage, given input voltages of Vx = +2 V and Vy = –10 V?

  • A. +2 V
  • B. +1 V
  • C. –2 V
  • D. –1 V

5. Amplitude modulation is a _____ process.

  • A. multiplication
  • B. division
  • C. sum/difference

6. The output spectrum of a _____ modulator includes upper-side and lower-side frequencies and the carrier frequency.

  • A. balanced
  • B. standard amplitude
  • C. none of the above

7. An AM demodulator can be implemented with a linear multiplier followed by a _____ filter.

  • A. low-pass
  • B. high-pass
  • C. band-pass
  • D. band-stop

8. What does VCO stand for?

  • A. Visually-Controlled Organization
  • B. Voltage-Controlled Oscillator
  • C. Voltage-Centered Oscilloscope

9. A phase-locked loop (PLL) is a feedback circuit consisting of a

  • A. phase detector.
  • B. low-pass filter.
  • C. VCO.
  • D. all of the above

10. Light may be propagated along a fiber-optic cable in which of the following modes?

  • A. multimode step index
  • B. single-mode step index
  • C. multimode graded index
  • D. all of the above

11. In order for a light ray to propagate along a fiber-optic cable, what must the relationship be between the angle of incidence and the critical angle?

  • A. θi > θc
  • B. θi < θc
  • C. θi = θc
  • D. none of the above

12. A certain fiber-optic cable has the following characteristics: n1 = 1.82 and n2 = 1.73. What is the value of θc?

  • A. 1.0º
  • B. 0.95º
  • C. 18.1º
  • D. 1.81º


1. Amplitude modulation is the process of varying the radio frequency with the modulating frequency.

  • A. True
  • B. False

2. The purpose of the balanced modulator is to remove the carrier frequency.

  • A. True
  • B. False

3. An AM signal is made up of a carrier, an upper-side frequency, and a lower-side frequency.

  • A. True
  • B. False

4. The mixer takes the RF signal along with the audio signal to produce the IF signal.

  • A. True
  • B. False

5. Selectivity in a receiver is provided by the resonant circuits of the IF section.

  • A. True
  • B. False

6. Frequency modulation is achieved by varying the frequency of an oscillator with a modulating signal.

  • A. True
  • B. False

7. A VCO is a variable capacitance oscillator.

  • A. True
  • B. False

8. The demodulator recovers the audio signal from the IF output.

  • A. True
  • B. False

9. The IF of an FM receiver operates at a center frequency of 455 kHz.

  • A. True
  • B. False

10. A balanced modulator is used in standard AM to obtain the sum and difference frequencies.

  • A. True
  • B. False

Check your work.

Complete List of Chapter MCQs in Floyd’s Electronic Devices

MCQs in Communications
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