Pulse average intensity (Ipa) is averaged _________.

Pulse average intensity (Ipa) is averaged _________.

• A. On time only
• B. Off time only
• C. PRP
• D. Entire cycle

Answer: (A)

Pulse average intensity is defined by averaging during the actual emission window. In pulsed ultrasound, the beam turns on (emits) for a certain duration and then turns off. I_pa captures the mean intensity only over that on-time period, because during the off-time there is no emission (intensity is zero) and isn’t included in this average. If you averaged over the entire cycle (on plus off), you’d be looking at a temporal-average quantity, not the pulse-average one. Pulse repetition period (PRP) is about how long the cycle lasts, not how the intensity is averaged. So the correct description is that I_pa is averaged during the on time only.

Pulse average intensity is defined by averaging during the actual emission window. In pulsed ultrasound, the beam turns on (emits) for a certain duration and then turns off. I_pa captures the mean intensity only over that on-time period, because during the off-time there is no emission (intensity is zero) and isn’t included in this average. If you averaged over the entire cycle (on plus off), you’d be looking at a temporal-average quantity, not the pulse-average one. Pulse repetition period (PRP) is about how long the cycle lasts, not how the intensity is averaged. So the correct description is that I_pa is averaged during the on time only.