Which statement describes a single emitted pulse's duration?

Which statement describes a single emitted pulse's duration?

• A. It is the time length of the pulse
• B. It is the listening time
• C. It is the time between pulses
• D. It is the speed of sound

Answer: (A)

The duration of a single emitted pulse is the time length of the pulse, from the moment it starts to when it ends. This pulse duration depends on how many cycles are included in the pulse and the period of the ultrasound wave—more cycles or a longer period lengthen the pulse. For example, a pulse consisting of two cycles at 2 MHz lasts about 1 microsecond. The other terms describe related but different ideas: listening time is the receive window after emission, the time between pulses is the interval before the next emission, and the speed of sound is how fast the wave travels through tissue.

The duration of a single emitted pulse is the time length of the pulse, from the moment it starts to when it ends. This pulse duration depends on how many cycles are included in the pulse and the period of the ultrasound wave—more cycles or a longer period lengthen the pulse. For example, a pulse consisting of two cycles at 2 MHz lasts about 1 microsecond. The other terms describe related but different ideas: listening time is the receive window after emission, the time between pulses is the interval before the next emission, and the speed of sound is how fast the wave travels through tissue.