Which duty cycle values indicate pulsed ultrasound?

Which duty cycle values indicate pulsed ultrasound?

• A. 100
• B. 20 and 50
• C. 0
• D. 80

Answer: (B)

Duty cycle is the fraction of time the ultrasound is actually emitting during one cycle. Pulsed ultrasound emits in bursts with off intervals, so the duty cycle is greater than zero but less than 100%. Values like 20% and 50% clearly show on-and-off activity, which is what defines pulsed emission. A value of 0% means no emission at all, while 100% means continuous emission with no pause, not pulsed. Among the choices, 20% and 50% best illustrate the pulsed pattern by having definite “on” times separated by pauses.

Duty cycle is the fraction of time the ultrasound is actually emitting during one cycle. Pulsed ultrasound emits in bursts with off intervals, so the duty cycle is greater than zero but less than 100%. Values like 20% and 50% clearly show on-and-off activity, which is what defines pulsed emission. A value of 0% means no emission at all, while 100% means continuous emission with no pause, not pulsed. Among the choices, 20% and 50% best illustrate the pulsed pattern by having definite “on” times separated by pauses.