3D1X3 CDC Volume 1 Ure

100 Questions | Total Attempts: 1995

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3d1x3 Quizzes & Trivia

Read the damn title also jones.


Questions and Answers
  • 1. 
    (001)  What reason for modulation involves modulating low frequency signals for transmission over long distances?
    • A. 

      Spectrum conservation

    • B. 

      Channel allocation

    • C. 

      Ease of radiation

    • D. 

      Companding

  • 2. 
    (001)  What are the three general categories used to produce modulation in radio frequency (RF) transmission today?
    • A. 

      Binary amplitude shift keying, frequency shift keying, and phase shift keying.

    • B. 

      Pulse amplitude, pulse width, and pulse position.

    • C. 

      Amplitude, frequency, and phase.

    • D. 

      Analog, digital, and shift keying.

  • 3. 
    (002)  When the modulating signal and carrier signal are combined within a modulator, the output signal contains a/an
    • A. 

      Modulating signal, upper sideband, lower sideband.

    • B. 

      Carrier, upper sideband, and lower sideband.

    • C. 

      Upper sideband and modulating signal.

    • D. 

      Carrier and modulating signal.

  • 4. 
    (002)  If a carrier frequency of 1 MHz and a modulating tone of 10 kHz goes to the modulator, the output signal includes
    • A. 

      1.01 MHz, 1 MHz, and 0.99 MHz.

    • B. 

      1.1 MHz, 1 MHz, and 0.9 MHz.

    • C. 

      1.11 MHz, 1 MHz, 0.99 MHz.

    • D. 

      1.111 MHz, 1 MHz, 0.999 MHz

  • 5. 
    (002)  If the modulating audio signal is 10kHz wide, what is the bandwidth of the transmitted amplitude modulated signal?
    • A. 

      5 kHz

    • B. 

      10 kHz

    • C. 

      15 kHz

    • D. 

      20 kHz

  • 6. 
    (002)  The bandwidth of an amplitude modulated signal is
    • A. 

      Two times the modulating signal.

    • B. 

      The same as the modulating signal.

    • C. 

      Determined by modulation index.

    • D. 

      Defined in terms of maximum amount of modulation.

  • 7. 
    (002)  The amount of effect or change that the intelligence has on the carrier in an amplitude modulated signal is expressed as the
    • A. 

      Percent of modulation.

    • B. 

      Modulation index.

    • C. 

      Bandwidth.

    • D. 

      Deviation.

  • 8. 
    (002)  Which statement concerning bandwidth is true?
    • A. 

      Overmodulating increases bandwidth due to the production of harmonics.

    • B. 

      Undermodulating increases bandwidth due to the production of harmonics.

    • C. 

      Overmodulating increases bandwidth due to the output's increased amplitude.

    • D. 

      Undermodulating increases bandwidth due to the output's increased amplitude.

  • 9. 
    (002)  Reducing modulation to less than 100 percent gives
    • A. 

      More total power.

    • B. 

      A reduction in carrier power.

    • C. 

      No reduction in carrier power.

    • D. 

      A reduction in carrier and sideband power.

  • 10. 
    (003)  In frequency modulation (FM), the amount of oscillator frequency change is
    • A. 

      Inversely proportional to the amplitude of the modulating signal.

    • B. 

      Directly proportional to the amplitude of the modulating signal.

    • C. 

      Inversely proportional to the phase of the modulating signal.

    • D. 

      Directly proportional to the phase of the modulating signal.

  • 11. 
    (003)  In frequency modulation (FM), what is considered a significant sideband?
    • A. 

      Sidebands containing at least 1 percent of the total transmitted power.

    • B. 

      Sidebands containing at least 3 percent of the total transmitted power.

    • C. 

      Sidebands containing at least 10 percent of the total transmitted power.

    • D. 

      Sidebands containing at least 0.1 percent of the total transmitted power.

  • 12. 
    (003)  What is the formula to find the modulating index?
    • A. 

      Deviation divided by frequency of modulation.

    • B. 

      Deviation times frequency of modulation.

    • C. 

      Sideband divided by carrier frequency.

    • D. 

      Sideband times carrier frequency.

  • 13. 
    (004)  In phase modulation (PM), the carrier's
    • A. 

      Phase is shifted at the rate of the modulating signal.

    • B. 

      Phase shifted with the phase of the modulating signal.

    • C. 

      Amplitude is shifted at the rate of the modulating signal.

    • D. 

      Amplitude is shifted with the phase of the modulating signal.

  • 14. 
    (004)  What is the advantage of adding more phase shifts?
    • A. 

      Easier detection.

    • B. 

      Smaller bit error rate.

    • C. 

      Better signal-to-noise ratio.

    • D. 

      Higher data rates within a given bandwidth.

  • 15. 
    (005)  What is the first step in the pulse code modulation (PCM) process?
    • A. 

      Discrete amplitudes are assigned to the sampling pulses.

    • B. 

      A binary code number is assigned to the sample.

    • C. 

      The quantizer limits the amplitude of the pulses.

    • D. 

      The analog signal is band-limited.

  • 16. 
    (005)  What part of the pulse code modulation (PCM) process converts a continuous time signal into a discrete time signal?
    • A. 

      Sampling.

    • B. 

      Rectifying.

    • C. 

      Oscillating.

    • D. 

      Band limiting.

  • 17. 
    (005)  A type of pulse modulation (PM) that changes the amplitude of the pulse train to vary according to the amplitude of the input signal is called
    • A. 

      Pulse width modulation (PWM).

    • B. 

      Pulse position modulation.

    • C. 

      Pulse duration modulation.

    • D. 

      Pulse amplitude modulation.

  • 18. 
    (006)  If an error should occur, what data transmission is lost in a synchronous transmission?
    • A. 

      One character.

    • B. 

      Block of data.

    • C. 

      A parity bit.

    • D. 

      Synchronization (SYNC) bit.

  • 19. 
    (007)  When using vertical redundancy check (VRC), what significance does the amount of ones have in a data bit pattern?
    • A. 

      Determines parity.

    • B. 

      Determines transmission rate.

    • C. 

      Determines whether transmission is in American Standard code for Information Interchange (ASCII) format.

    • D. 

      Determines whether transmission is synchronous or asynchronous.

  • 20. 
    (007)  What two error detection methods, when used together, are 98 perfent effective in detecting errors?
    • A. 

      Checksum and cyclic redundancy check.

    • B. 

      Longitudinal redundancy check and checksum.

    • C. 

      Cyclic redundancy check and vertical redundancy check.

    • D. 

      Vertical redundancy check and longitudinal redundancy check.

  • 21. 
    (007)  What error detection method adds stacked characters, divides it by 255, and disregards the answer except for the remainder?
    • A. 

      Checksum.

    • B. 

      Block check character.

    • C. 

      Cyclic redundancy check.

    • D. 

      Vertical redundancy check.

  • 22. 
    (007)  What error-correction technique sends a retransmittal request by the receiver to the sender if it finds an error in a received frame?
    • A. 

      Error-correcting code.

    • B. 

      Forward error control.

    • C. 

      Redundant data transfer.

    • D. 

      Automatic retransmit on request.

  • 23. 
    (007)  When using forward error control as a method of error correction, where does error correction take place?
    • A. 

      Receiving end.

    • B. 

      In the oscillator.

    • C. 

      Transmitting end.

    • D. 

      In the primary buffers.

  • 24. 
    (008)  What does an optical source do?
    • A. 

      Terminates fober optics cable.

    • B. 

      Converts electrical energy into optical energy.

    • C. 

      Extend the distance and to preserve signal integrity.

    • D. 

      Accepts optical signals and converts them into electrical signals.

  • 25. 
    (008)  Light sources that are applicable to fiber optic waveguide are light-emitting diodes (LED) and
    • A. 

      Photo transistors.

    • B. 

      Hybrid photodiodes.

    • C. 

      Semiconductor laser diodes.

    • D. 

      Integrated photodiode/preamplifiers.