What are the 4 characteristics of shallow imaging?

• A. Less listening; Shorter PRP; Higher PRF; Higher duty factor
• B. More listening; Longer PRP; Lower PRF; Lower duty factor
• C. Less listening; Longer PRP; Higher PRF; Lower duty factor
• D. More listening; Shorter PRP; Higher PRF; Higher duty factor

Answer: (A)

Shallow imaging prioritizes speed, so the system hunts for a high frame rate by increasing the pulse repetition frequency and reducing the time spent listening to echoes. Echoes from near structures return quickly, which means you only need a shorter listening window before the next pulse. That shorter listening window corresponds to a shorter pulse repetition period, which in turn raises the pulse repetition frequency. As the cycle becomes shorter, a larger portion of each cycle is spent transmitting relative to listening, so the duty factor increases. Put together, you get less listening time, a shorter PRP, a higher PRF, and a higher duty factor—precisely what supports rapid, shallow imaging.