18
2-60. To transmit intelligence using pulse
modulation, which of the following pulse
characteristics may be varied?
1. Pulse duration
2. Pulse amplitude
3. Pulse-repetition time
4. Each of the above
2-61. To accurately reproduce a modulating
signal in a pulse-modulated system, what
minimum number of samples must be
taken per cycle?
1. One
2. Two
3. Three
4. Four
2-62. What is the simplest form of pulse
modulation?
1. Pulse-code modulation
2. Pulse-duration modulation
3. Pulse-frequency modulation
4. Pulse-amplitude modulation
2-63. The same pulse characteristic is varied in
which of the following types of pulse
modulations?
1. Pam and pdm
2. Pdm and pwm
3. Pwm and ppm
4. Ppm and pam
THIS SPACE LEFT BLANK
INTENTIONALLY.
Figure 2G.—Waveform.
IN ANSWERING QUESTION 2-64, REFER TO
FIGURE 2G.
2-64. Which of the points shown in the
waveform may be varied in pulse-duration
modulation?
1. A only
2. B only
3. C only
4. A and/or C
2-65. Which, if any, of the following is the
primary disadvantage of pulse-position
modulation?
1. It depends on transmitter-receiver
synchronization
2. It is susceptible to noise interference
3. Transmitter power varies
4. None of the above
2-66. A pfm transmitter transmits 10,000 pulses
per second without a modulating signal
applied. How, if at all, will a modulating
signal affect the transmitted pulse rate?
1. It will decrease the transmitted pulse
rate
2. It will increase the transmitted pulse
rate
3. Both 1 and 2 above
4. It will not affect the transmitted pulse
rate
