ECT 263 Week 8 Final Exam

1. (TCO 1) Calculate the wavelength of a 950KHz carrier signal. (Points : 6)

2. FM signal has shorter wavelength than AM. (Points : 6)

3. FM travels longer distance than AM. (Points : 6)

4. Frequency modulation means that the carrier frequency increases and decreases according the rise and fall of the amplitude of modulation signal. (Points : 6)

5. Amplitude modulation means that the carrier amplitude increases and decreases according the rise and fall of the amplitude of modulation signal. (Points : 6)

6. In the frequency spectrum of an AM signal, the spacing between the carrier and either of the sidebands is the modulation frequency. (Points : 6)

7. A Spectral Analyzer is an instrument that displays a graph of amplitude on the y-axis as a function of time on the x-axis. (Points : 6)

8. (TCO 1) The following response curve would be produced by what kind of filter?

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40. Continue from the previous on FM Modulator, the Modulation Factor, m = ______ (Points : 6)

41. Continue from previous question on FM Modulator, How many pairs of side bands (refer to Bessell Chart below) in this FM frequency spectrum?

42. Continue from previous question on FM Modulator,
the bandwidth required to transmit this FM signal is _________________ (Points : 6)

43. Phase Locked Loop (PLL) system is used to lock in the frequency of two signals. (Points : 6)

44. A pure SINE wave signal has no side bands (i.e., no harmonics) in its frequency spectrum shown in the spectral analyzer. (Points : 6)

45. For PLL system below, which block (i.e. shown as a number in a circle) is the phase comparator?

46. Continue from the previous question, the input signal (i.e., the reference signal) to the PLL system can be measured from the output of which block ? (Points : 6)

47. Continue from the previous question, the Phase Locked Loop system is used to lock in two signals, from the PLL implementation in the Tims block diagram, the two signals are:

48. FM receiver is basically an "envelope detector". (Points : 6)

49.

AM receiver does not need an AGC (Automatic Gain Control) feedback path

50. Intermediate frequency (IF) amplifiers in the superheterodyne receivers are band-pass filter. (Points : 6)

51. The last stage of the FM modulation is a low-pass filter

52. In TutorTims, the last stage of the AM modulator is a multiplier. (Points : 6)