This is the Multiple Choice Questions (MCQs) in Chapter 26: Data Transmission from the book Teach Yourself Electricity and Electronics, 5th edition by Stan Gibilisco. If you are looking for a reviewer in Electronics Engineering this will definitely help you before taking the Board Exam.
Practice Exam Test Questions
1. A radio wave has a frequency of 1.55 MHz. The highest modulating frequency that can be used effectively is about:
- A. 1.55 kHz.
- B. 15.5 kHz.
- C. 155 kHz.
- D. 1.55 MHz.
2. Morse code is a form of:
- A. Digital modulation.
- B. Analog modulation.
- C. Phase modulation.
- D. dc modulation.
3. An advantage of FSK over simple on-off keying for RTTY is:
- A. Better frequency stability.
- B. Higher speed capability.
- C. Reduced number of misprints.
- D. On-off keying is just as good as FSK.
4. The maximum AM percentage possible without distortion is:
- A. 33 percent.
- B. 67 percent.
- C. 100 percent.
- D. 150 percent.
5. If an AM signal is modulated with audio having frequencies up to 5 kHz, then the complete signal bandwidth will be:
- A. 10 kHz.
- B. 6 kHz.
- C. 5 kHz.
- D. 3 kHz.
6. An AM transmitter using a class-C PA should employ:
- A. Carrier suppression.
- B. High-level modulation.
- C. Lower sideband.
- D. Single sideband.
7. Which of the following modulation methods is used to send teleprinter data over the phone lines?
- A. CW.
- B. SSB.
- C. AM.
- D. AFSK.
8. An advantage of SSB over AM is:
- A. Higher data transmission rate.
- B. More effective use of transmitter power.
- C. Greater bandwidth.
- D. Enhanced carrier wave level.
9. An SSB suppressed carrier is at 14.335 MHz. The voice data is contained in a band from 14.335-14.338 MHz. The mode is:
- A. AM.
- B. LSB.
- C. USB.
- D. FSK.
10. A spectrum analyzer displays:
- A. Time as a function of frequency.
- B. Frequency as a function of time.
- C. Signal strength as a function of time.
- D. Signal strength as a function of frequency.
11. The deviation for voice FM signals is usually:
- A. Plus-or-minus 3 kHz.
- B. Plus-or-minus 5 kHz
- C. Plus-or-minus 6 kHz.
- D. Plus-or-minus 10 kHz.
12. Wideband FM is preferable to narrowband FM for music transmission because:
- A. Lower frequencies are heard better.
- B. Spectrum space is conserved.
- C. The fidelity is better.
- D. No! Narrowband FM is better for music.
13. In which mode of PM does the pulse level vary?
- A. PAM.
- B. PDM.
- C. PWM.
- D. PFM.
14. In which PM mode do pulses last for varying times?
- A. PAM.
- B. PWM.
- C. PFM.
- D. PCM.
15. How many states are commonly used for the transmission of digitized voice signals?
- A. Two.
- B. Four.
- C. Six.
- D. Eight.
16. In an SSTV signal, the frame time is:
- A. 1/525 second.
- B. 1/30 second.
- C. 1/8 second.
- D. Eight.
- D. 8 seconds.
17. The bandwidth of a fax signal is kept narrow by:
- A. Sending the data at a slow rate of speed.
- B. Limiting the image resolution.
- C. Limiting the range of shades sent.
- D. Using pulse modulation.
18. What is the wavelength of a 21.3-MHz signal?
- A. 46.2 m.
- B. 14.1 m.
- C. 21.0 km.
- D. 6.39 km.
19. A coaxial cable:
- A. Keeps the signal confined.
- B. Radiates efficiently.
- C. Works well as a transmitting antenna.
- D. Can pick up signals from outside.
20. An advantage of fiber optics over cable communications is:
- A. More sensitivity to noise.
- B. Improved antenna efficiency.
- C. Higher RF output.
- D. Simpler and easier maintenance.
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