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Figure 3I.—Detector.
IN ANSWERING QUESTIONS 3-50
THROUGH 3-52, REFER TO FIGURE 3I.
3-50. To detect pulse-amplitude modulation,
what value must the RC time constant of
R1 and C1 in the circuit be?
1. Five times the pulse width
2. Ten times the pulse width
3. Five times the interpulse period
4. Ten times the interpulse period
3-51. Which, if any, of the following functions
is the purpose of CR2?
1. To quickly discharge C1 between
received pulses
2. To rectify input pulses
3. To clamp the output to a positive
level
4. None of the above
3-52. What change must be made to the circuit
to detect pulse-duration modulation?
1. Remove R1
2. Increase the value of R1
3. Decrease the value of R1
4. Add a resistor in series with CR1
3-53. When a pulse-duration modulated signal
is determined by using a low-pass filter,
what characteristic of the signal is used?
1. Width
2. Amplitude
3. Frequency
4. Pulse position
3-54. To detect pulse-duration modulation, the
low-pass filter components must be
selected so that they pass only the
1. carrier frequency
2. intermediate frequency
3. pulse-repetition frequency
4. desired modulating frequency
3-55. What type(s) of modulation is/are
normally detected by first converting
it/them to another type of modulation?
1. Ppm only
2. Pfm only
3. Pcm only
4. Ppm, pfm, and pcm
3-56. What type of circuit can be used to
convert from ppm to pdm for
demodulation?
1. An amplifier
2. A flip-flop
3. An oscillator
4. A transformer
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