Chapter 4: Describing Pulsed Waves Flashcards
What is a pulsed sound?
a collection of cycles that travel together
What is a pulse made up of?
individual cycles
Two components of pulsed ultrasound
- transmit, talking, “on time”
-receive, listening, “off time”
Pulse duration
-the actual time from the start of a pulse to the end of that pulse
- a single “on” time
Pulse duration & relationships with cycles, period and frequency
-directly proportional to # of cycles
-directly proportional to period
-inversely proportional to frequency
long pulse duration
-many cycles in a pulse
-individual cycles with long periods
short pulse duration
-few cycles in a pulse
-individual cycles with short periods
Shorter duration pulses are more desirable b/c they create images of greater accuracy
Spatial Pulse Length
distance from the start to the end of a pulse
Spatial Pulse Length and relationships with cycles, wavelength, and frequency
-directly proportional to # of cycles in pulse
-directly proportional to wavelength
-directly proportional to frequency
Difference between pulse duration and spatial pulse length?
SPL- the distance of the pulse end to end
Pulse duration- time of pulse from beginning to end
Long pulse length
-many cycles in pulse
-longer wavelengths
Short pulse length
-fewer cycles in the pulse
-shorter wavelengths
Why are short pulses more desirable?
they create more accurate images and higher frequency sound waves
Pulse Repetition Period (PRP)
-time from start of one pulse to the start of the next pulse
-includes both “on” and “off” time
-reported in units of time
-directly related to imaging depth
Depth of View
maximum distance into the body that an ultrasound system is imaging
