By adjusting the imaging depth the operator changes what 3 things?

By adjusting the imaging depth the operator changes what 3 things?

• A. Pulse duration; PRP; Duty factor
• B. PRP; Pulse duration; Duty factor
• C. PRP; PRF; Duty factor
• D. PRP; PRF; Pulse duration

Answer: (C)

Imaging depth determines how long the system listens between sending pulses and how often pulses can be sent. The time from the start of one pulse to the start of the next is the Pulse Repetition Period. When you image deeper, echoes take longer to return, so the system must wait longer before emitting the next pulse, increasing the PRP. Since Pulse Repetition Frequency is how many pulses are emitted per second, a longer PRP means a smaller PRF. The duty factor, which is the fraction of time the system is actually emitting a pulse, depends on the pulse duration divided by the PRP. The pulse duration is set by the transducer and excitation and doesn't change with depth, so as PRP grows with depth, the duty factor drops. So deeper imaging leads to higher PRP, lower PRF, and lower duty factor.

Imaging depth determines how long the system listens between sending pulses and how often pulses can be sent. The time from the start of one pulse to the start of the next is the Pulse Repetition Period. When you image deeper, echoes take longer to return, so the system must wait longer before emitting the next pulse, increasing the PRP. Since Pulse Repetition Frequency is how many pulses are emitted per second, a longer PRP means a smaller PRF. The duty factor, which is the fraction of time the system is actually emitting a pulse, depends on the pulse duration divided by the PRP. The pulse duration is set by the transducer and excitation and doesn't change with depth, so as PRP grows with depth, the duty factor drops. So deeper imaging leads to higher PRP, lower PRF, and lower duty factor.