Describing Pulsed Waves class notes

Flashcards based on the lecture notes about describing pulsed waves.

Pulse Duration

The actual time from the beginning to the end of a pulse, also known as transmit time, typically ranging from 0.3 to 2.0 microseconds.

What is pulse duration determined by

Sound source only

Pulse Duration Formula 1

Pulse direction= # of cycles * period of cycles

Pulse Duration Formula 2

Pulse Duration = # of cycles / Frequency

Pulse Duration relationship:

Directly proportional to number of cycles in pulse

Spatial Pulse Length

The distance in space occupied by a pulse from beginning to end, usually between 0.1 to 1 mm.

Spatial Pulse Length Formula

Spatial Pulse Length = Number of cycles in pulse * wavelength of each cycle

Pulse Repetition Period (PRP)

The time from the start of one pulse to the start of the next pulse, ranging from 100 microseconds to one millisecond.

How is PRP determined?

Adjusted by imaging depth controls.

Pulse Repetition Frequency (PRF)

The number of pulses transmitted into the body per second, ranging from 1000 to 10,000 Hz.

How is PRF adjusted?

Adjusted via imaging depth.

How are PRP and PRF Related? (Formula 1)

PRF = 1/PRP

How are PRP and PRF Related? (Formula 2)

PRP = 1/PRF

Duty Factor

The percentage of time the system is transmitting a pulse, typically 0.25-0.5%.

Continuous Wave Duty Factor

A continuous wave has a duty factor of 100%.

Duty Factor Relationship to Imaging Depth

Inversely related to imaging depth.

What is Intensity?

Beam’s power divided by its area

What does 'Spatial' Refer to with Intensity?

Spatial Peak Intensity

Spatial Average Intensity

Spatial Average Intensity

Temporal Peak Intensity

Maximum Intensity-Average intensity during most intense half cycle

Pulse Average Intensity

Average Intensity during pulse duration

Temporal Average Intensity

Average intensity during pulse repetition period

SPTP

spatial peak, temporal peak

SATP

spatial average, temporal peak

SPTA

spatial peak, temporal average

SATA

spatial average, temporal average

SPPA

spatial peak, pulse average

SAPA

spatial average, pulse average