Key Topic 59: Pulse Modulation

Question 1

3-59H1: What is an important factor in pulse-code modulation using time-division multiplex?

A. Synchronization of transmit and receive clock pulse rates.
B. Frequency separation.
C. Overmodulation and undermodulation.
D. Slight variations in power supply voltage.

Answer 1

A. Synchronization of transmit and receive clock pulse rates.

Question 2

3-59H2: In a pulse-width modulation system, what parameter does the modulating signal vary?

A. Pulse frequency.
B. Pulse duration.
C. Pulse amplitude.
D. Pulse intensity.

Answer 2

B. Pulse duration.

Question 3

3-59H3: What is the name of the type of modulation in which the modulating signal varies the duration of the transmitted pulse?

A. Amplitude modulation.
B. Frequency modulation.
C. Pulse-height modulation.
D. Pulse-width modulation.

Answer 3

D. Pulse-width modulation.

Question 4

3-59H4: Which of the following best describes a pulse modulation system?

A. The peak transmitter power is normally much greater than the average power.
B. Pulse modulation is sometimes used in SSB voice transmitters.
C. The average power is normally only slightly below the peak power.
D. The peak power is normally twice as high as the average power.

Answer 4

A. The peak transmitter power is normally much greater than the average power.

Question 5

3-59H5: In a pulse-position modulation system, what parameter does the modulating signal vary?

A. The number of pulses per second.
B. The time at which each pulse occurs.
C. Both the frequency and amplitude of the pulses.
D. The duration of the pulses.

Answer 5

B. The time at which each pulse occurs.

Question 6

3-59H6: What is one way that voice is transmitted in a pulse-width modulation system?

A. A standard pulse is varied in amplitude by an amount depending on the voice waveform at that instant.
B. The position of a standard pulse is varied by an amount depending on the voice waveform at that instant.
C. A standard pulse is varied in duration by an amount depending on the voice waveform at that instant.
D. The number of standard pulses per second varies depending on the voice waveform at that instant.

Answer 6

C. A standard pulse is varied in duration by an amount depending on the voice waveform at that instant.