Which statement best describes the relationship between pulse duration and PRP?

Which statement best describes the relationship between pulse duration and PRP?

• A. PRP is typically 1 to 2 times longer than pulse duration
• B. PRP is typically shorter than pulse duration
• C. PRP is typically 100 to 1000 times longer than pulse duration
• D. PRP is identical to pulse duration

Answer: (C)

The key idea is that pulse duration is how long a single transmitted burst lasts, while the pulse repetition period is the entire interval from the start of one burst to the start of the next. Because the system must listen for echoes after each pulse and avoid overlapping the next transmitted burst with those echoes, the interval between starts is much longer than the burst itself. In practice, this interval is typically hundreds to thousands of times longer than the pulse width, which is why PRP is described as 100 to 1000 times longer than the pulse duration. Remember, PRP and PRF are linked: a longer PRP means a lower pulse repetition frequency. If the PRP were only a little longer than the pulse duration or shorter than it, echoes from distant targets would overlap with the next pulse, making it impossible to process returns cleanly. An identical PRP and pulse duration would leave no time to listen for echoes at all. Hence the widely used relationship where PRP vastly exceeds the pulse duration.

The key idea is that pulse duration is how long a single transmitted burst lasts, while the pulse repetition period is the entire interval from the start of one burst to the start of the next. Because the system must listen for echoes after each pulse and avoid overlapping the next transmitted burst with those echoes, the interval between starts is much longer than the burst itself. In practice, this interval is typically hundreds to thousands of times longer than the pulse width, which is why PRP is described as 100 to 1000 times longer than the pulse duration. Remember, PRP and PRF are linked: a longer PRP means a lower pulse repetition frequency.

If the PRP were only a little longer than the pulse duration or shorter than it, echoes from distant targets would overlap with the next pulse, making it impossible to process returns cleanly. An identical PRP and pulse duration would leave no time to listen for echoes at all. Hence the widely used relationship where PRP vastly exceeds the pulse duration.