Gibilisco - Wireless Transmitters And Receivers

20 Questions | Total Attempts: 112

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Wireless Quizzes & Trivia

Questions and Answers
  • 1. 
    A radio wave has a frequency of 1.55 MHz. The highest modulating frequency that can beused effectively is about
    • A. 

      1.55 kHz.

    • B. 

      15.5 kHz.

    • C. 

      155 kHz.

    • D. 

      1.55 MHz.

  • 2. 
    The reflected wave
    • A. 

      Arrives in phase with the direct wave.

    • B. 

      Arrives out of phase with the direct wave.

    • C. 

      Arrives in a variable phase compared with the direct wave.

    • D. 

      Is always horizontally polarized.

  • 3. 
    An advantage of FSK over on/off keying is the fact that FSK
    • A. 

      Offers better frequency stability.

    • B. 

      Can provide faster data rates.

    • C. 

      Reduces the number of receiving errors.

    • D. 

      Forget it! On-off keying is just as good as FSK.

  • 4. 
    The highest layer of the ionosphere is
    • A. 

      The D layer.

    • B. 

      The E layer.

    • C. 

      The F layer.

    • D. 

      None of the above.

  • 5. 
    If an AM signal is modulated with audio having frequencies up to 5 kHz, then what is thecomplete signal bandwidth?
    • A. 

      10 kHz

    • B. 

      20 kHz

    • C. 

      50 kHz

    • D. 

      500 kHz

  • 6. 
    An LSB, suppressed-carrier signal can be demodulated by
    • A. 

      An envelope detector.

    • B. 

      A diode.

    • C. 

      A ratio detector.

    • D. 

      A product detector.

  • 7. 
    Which of the following modes is used to send image data over telephone lines?
    • A. 

      On/off keying

    • B. 

      Fax

    • C. 

      AM

    • D. 

      Product detection

  • 8. 
    The S/N ratio is a measure of
    • A. 

      The sensitivity of a receiver.

    • B. 

      The selectivity of a receiver.

    • C. 

      The dynamic range of a receiver.

    • D. 

      The efficiency of a transmitter.

  • 9. 
    Suppose an SSB suppressed carrier is at 14.335 MHz, and audio data is contained in a bandfrom 14.335 to 14.338 MHz. What is this mode?
    • A. 

      DSB

    • B. 

      LSB

    • C. 

      USB

    • D. 

      AFSK

  • 10. 
    A receiver that responds to a desired signal, but not to another signal very close by infrequency, has good
    • A. 

      Sensitivity.

    • B. 

      Noise figure.

    • C. 

      Dynamic range.

    • D. 

      Selectivity.

  • 11. 
    Fill in the blank in the following sentence to make it true: “The deviation of a narrowbandvoice FM signal normally extends up to either side of the unmodulated-carrier frequency.”
    • A. 

      3 kHz

    • B. 

      5 kHz

    • C. 

      10 kHz

    • D. 

      3 MHz

  • 12. 
    An FM detector with built-in limiting is
    • A. 

      A ratio detector.

    • B. 

      A discriminator.

    • C. 

      An envelope detector.

    • D. 

      A product detector.

  • 13. 
    In which mode of PM does the peak power level of the pulses vary?
    • A. 

      PAM

    • B. 

      PDM

    • C. 

      PIM

    • D. 

      PFM

  • 14. 
    A continuously variable signal (such as music audio) can be recovered from a signal havingonly a few discrete levels or states by means of
    • A. 

      A ratio detector.

    • B. 

      A D/A converter.

    • C. 

      A product detector.

    • D. 

      An envelope detector.

  • 15. 
    In which mode are signals intertwined in the time domain at the transmitter, and thenseparated again at the receiver?
    • A. 

      FDM

    • B. 

      AFSK

    • C. 

      PCM

    • D. 

      None of the above

  • 16. 
    Which of the following modes can be demodulated with an envelope detector?
    • A. 

      AM

    • B. 

      CW

    • C. 

      FSK

    • D. 

      USB

  • 17. 
    The bandwidth of a fax signal is kept narrow by
    • A. 

      Sending the data at a slow rate of speed.

    • B. 

      Maximizing the number of digital states.

    • C. 

      Optimizing the range of colors sent.

    • D. 

      Using pulse modulation.

  • 18. 
    The dynamic range in a superhet is largely influenced by the performance of the
    • A. 

      Local oscillator.

    • B. 

      Product detector.

    • C. 

      Front end.

    • D. 

      Selectivity in the IF chain.

  • 19. 
    Frequency sweeping can be used to get a transmitter to produce
    • A. 

      Spread-spectrum signals.

    • B. 

      Time division multiplexed signals.

    • C. 

      Narrowband AM signals.

    • D. 

      Double sideband, suppressed carrier signals.

  • 20. 
    Fill in the blank to make the following sentence true: “The reception of can beimproved by the use of DSP.”
    • A. 

      SSB signals

    • B. 

      SSTV signals

    • C. 

      Synchronized communications signals

    • D. 

      Any of the above

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