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Electronic Communications Systems Tomasi Chapter 7 And 8

47 Questions
Communication Quizzes & Trivia

Electronic communications systems subject

Questions and Answers
  • 1. 
    Results whenever the phase angle of a sinusoidal wave is varied with respect to tiime
  • 2. 
    Angle Modulation results whenever the _________ of a sinusoidal wave is varied with respect to time
  • 3. 
    The two forms of angle modulation are ________ and ________
  • 4. 
    _______ is varying the frequency of a constant amplitude carrier directly proportional to the amplitude of the modulating signal at a rate equal to the frequency of the modulating signal
  • 5. 
    __________ is varying the phase of a constant amplitude carrier directly proportional to the amplitude of the modulation signal at a rate equal to the frequency of the modulating signal
  • 6. 
    Direct frequency modulation is varying the frequency of a ______ amplitude carrier directly proportional to the amplitude of the modulating signal at a rate equal to the frequency of the modulating signal.
  • 7. 
    Direct frequency modulation is varying the frequency of a constant amplitude carrier _____ ______ to the amplitude of the modulating signal at a rate equal to the frequency of tthe modulating signal.
  • 8. 
    When _____ of a signal is varied, it's phase is also varied
  • 9. 
    The ______ between frequency and phase modulation lies in which property of the carrier is directly varied by the modulating signal.
  • 10. 
    The difference between frequency and phase modulation lies in which property of the carrier is ____ _____ by the modulating signal
  • 11. 
    If the modulating signal ______ the frequency directly, frequency modulation results
  • 12. 
    If the modulating signal varies the frequency directly, _____ ______ results
  • 13. 
    If the modulating signal varies the phase directly, ___ ____ results.
  • 14. 
    FM has the ability to ______ _____, which is probably the biggest advantage of FM compared to AM
  • 15. 
    FM receivers can be fitted with _____ ______ to remove amplitude variations caused by noise, making FM more immune to noise.
  • 16. 
    FM receivers can be fitted with amplitude limiters to remove amplitude variations caused by noise, making FM more immune to noise. This is called __ ________
  • 17. 
    In __, once the signal has been contaminated by noise, noise cannot be removed
  • 18. 
    _____ can be improved further by increasing the frequency deviation of FM signals
  • 19. 
    Signal to noise ratio can be improved further by increasing the ______ of FM signals
  • 20. 
    Reduced noise improves _____
  • 21. 
    _____ improves system fidelity
  • 22. 
    Angle modulated signals are more _________
  • 23. 
    Amplitude of FM and PM remains _____
  • 24. 
    Amplitude is _____ of modulation depth
  • 25. 
    In angle modulation, _____ may be used, but all subsequent can be class C and therefore more power efficient
  • 26. 
    In angle modulation, all transmitted power in FM are useful, making it more ______
  • 27. 
    Standard frequency allocations provide ______ between FM broadcast stations, so there is less adjacent channel interference.
  • 28. 
    Standard frequency allocations provide guard band between FM broadcast stations, so there is ____ adjacent channel interference
  • 29. 
    There is ____ noise in MF and HF than in VHF and UHF
  • 30. 
    For FM, the radius is limitted more than line of _____
  • 31. 
    For FM broadcasts, ______ is used, so that the radius of operation is limitted slightly more than line of sight
  • 32. 
    For FM broadcasts, several independent transmitters separated by space can use  the ____ frequency with less possible interference
  • 33. 
    With FM and PM, a phenomenon known as _____ allows a receiver to differentiate between two signals with the same frequency
  • 34. 
    In capture effect, the signals ratio, one of the signals is _____ as high as the other. 
  • 35. 
    In angle modulation, _____ bandwidth is needed compared to AM
  • 36. 
    In angle modulation, there is ____ complex circuits than in AM
  • 37. 
    In Angle modulation, since reception is limitted in line of sight, the area of reception is much _____ than AM.
  • 38. 
    In PM, when the carrier signal is not modulated, its frequency is constant and is equal to the ________
  • 39. 
    In PM, when the carrier signal is modulated by a modulating signal, its ________ will change depending on the instantaneous value of the modulating signal voltage.
  • 40. 
    In PM, the higher is the modulating signal voltage the higher is the ______
  • 41. 
    In PM, the higher is the peak amplitude of the modulating signal, the higher is the ____
  • 42. 
    In PM, the peak phase deviation occurs when the _____ of the modulating signal is at its peak.
  • 43. 
    In PM, while the phase of the carrier is changing, its frequency will also be changing. _____ FM will result
  • 44. 
    ____ indicates how much phase of the carrier is changing with respect to its reference phase.
  • 45. 
    ____ is the precise phase of the carrier at a given instant of time
  • 46. 
    In FM, when the carrier signal is modulated by a modulating signal, its instantaneous frequency will change depending on the ______ of the modulating signal
  • 47. 
    In FM, the higher is the modulating signal voltage, the higher is the _____