# Pulse Duration (PD), Pulse Repetition Period (PRP) and Duty Factor (DF)

• markieboy
In summary, the number of cycles in each pulse increases, the PRP increases, and the DF stays the same.
markieboy
Homework Statement
Pulse duration (PD) is the time from the start to the end of a pulse.
Pulse repetition period (PRP) is the time from the start of one pulse to the start of the next pulse.
Duty factor (DF) is the percentage of that time that sound is created by the transducer.

The number of cycles in each pulse increases:
1) The PD increases/decreases/stays the same.
2) The PRP increases/decreases/stays the same.
3) The DF increases/decreases/stays the same.

The number of pulses completed each second increases:
4) The PD increases/decreases/stays the same.
5) The PRP increases/decreases/stays the same.
6) The DF increases/decreases/stays the same.

The number of cycles completed each second increases:
7) The PD increases/decreases/stays the same.
8) The PRP increases/decreases/stays the same.
9) The DF increases/decreases/stays the same.
10) The number of cycles in each pulse increases/decreases/stays the same.
Relevant Equations
PD = (# of cycles)(period)
PRP = time/pulses
DF = (PD/PRP)*100
I attempted this assignment, and scored a 5/10. The solutions are not given until a later date. I need to understand this material before I progress to the next section. The following are my attempts at the solution.

The number of cycles in each pulse increases:
The PD is determined by the number of cycles and the period. If the number of cycles increases, the PD increases. One component of the PRP is the PD. So, the PRP increases. If both PD and PRP increases, the ratio of the DF stays the same.
1) The PD increases.
2) The PRP increases.
3) The DF stays the same.

The number of pulses completed each second increases:
This is the definition of PRF, which is the reciprocal of PRP. If PRF increases, PRP decreases. PD is not affected. It stays the same. Since only PRP decreases, DF increases.
4) The PD stays the same.
5) The PRP decreases.
6) The DF increases.

The number of cycles completed each second increases:
This is the definition of frequency, which is the reciprocal of period. PD is affected by the period. Frequency increases, period decreases. Therefore, PD will decrease. PRP will decrease. Since both decrease, the DF will remain the same. The number of cycles in each pulse stays the same.
7) The PD decreases.
8) The PRP decreases.
9) The DF stays the same.
10) The number of cycles in each pulse stays the same.

I am unsure what questions I got wrong. If someone can point out my errors, I would appreciate that very much.

Thank you!

Hi @markieboy,
!​

Could be my shortcoming, but in this story I miss something: am I supposed to assume a pulse consists of a number of cycles of a sound signal with a fixed frequency ?

That would explain the PD = (# of cycles)(period) relevant equation.

But why would that mean the PRP increases as well ? (your 2) answer )
Is there something in the full problem statement that gives you that impression ? Or did you type the full problem statement exactly as it was given to you ?
I would expect the signal generator to give a next pulse after a fixed time from the start of the previous pulse (not after the termination).

I agree with 6) 7) 8)

markieboy said:
PD is affected by the period
Why ? Number of cycles/second = frequency. The frequency increases but the PD can stay the same ?
That way PD, PRP and DF all three stay the same

Perhaps it's a good idea to make sketches of the waveforms ?

##\ ##

## What is Pulse Duration (PD)?

Pulse Duration (PD) is the length of time that a pulse of energy is transmitted. It is typically measured in microseconds (μs) or milliseconds (ms).

## What is Pulse Repetition Period (PRP)?

Pulse Repetition Period (PRP) is the time between the start of one pulse and the start of the next pulse. It is typically measured in microseconds (μs) or milliseconds (ms).

## What is Duty Factor (DF)?

Duty Factor (DF) is the ratio of the pulse duration to the pulse repetition period. It is expressed as a percentage or decimal number between 0 and 1.

## How are PD, PRP, and DF related?

PD, PRP, and DF are all related to each other through the equation DF = PD/PRP. This means that as the pulse duration or pulse repetition period changes, the duty factor will also change.

## Why are PD, PRP, and DF important in scientific research?

PD, PRP, and DF are important because they provide information about the characteristics of a pulse of energy, which can be used to determine the effects of the energy on a target. They are also important in understanding and optimizing the performance of devices that use pulsed energy, such as lasers and ultrasound machines.

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