Which term denotes the time from the start of one emitted pulse to the start of the next?

• A. PRP
• B. PRF
• C. Real Time Imaging
• D. Range Ambiguity

Answer: (A)

Pulse Repetition Period is the time from the start of one emitted pulse to the start of the next. It covers the duration of the transmitted pulse plus the listening time for echoes from the farthest depth, plus any idle time before the next pulse. This period sets how often pulses are sent, and is the reciprocal of the pulse repetition frequency: PRF = 1 / PRP. A longer PRP means a lower PRF, which allows more listening time for deeper echoes but reduces frame rate. If PRP is too short for the deepest depth you’re imaging, echoes from that depth can be misassigned to shallower locations—this is known as range ambiguity. Real-time imaging describes the rapid display of frames, which is influenced by PRF but is not the definition of PRP.