Chapter 4 Terms/ Relationships
____ is the actual time from the start of a pulse to the end of that pulse.
Pulse duration
Pulse duration is determined by_____.
sound source only
Is pulse duration adjustable?
No
What is the equation for pulse duration and period?
pulse duration = # of cycles x period
What is the equation for pulse duration and frequency?
pulse duration = # if cycles/ frequency
_____ duration have many cycles in the pulse or individual cycles with long periods.
Long
____ duration creat few cycles in the pulse or idividual cycles with short periods.
Short
_____ is the distance that a pulse occupies in space from the start to the end of a pulse.
Spatial pulse length
Spatial pulse length is determined by _____.
both the source and the medium
Is spatial pulse length adjustable?
No
Pulse duration is _____.
time
Spatial pulse length is ______.
distance
What is the equation for spatial pulse length and wavelength?
spatial pulse length = # of cycles x wavelength
Spatial pulse length is ________ to the number of cycles.
directly proportional
Spatial pulse length is _______ to wavelength.
directly proportional
Spatial pulse length is _______ to frequency.
inversely proportional
____ pulses have many cycles in the pulse or cycles with longer wavelengths.
Long
_____ pulses have fewer cycles or cycles with shorter wavelengths.
Short
Pulses of _____ length are desirable.
shorter
Pulses of ____ duration are desirable.
shorter
________ is the time from the start of one pulse to the start of the next pulse.
Pulse repetition period
Pulse repetition period is determined by the___.
sound source only
Pulse repetition period is determined by the _______ that the sonographer selects.
imaging depths
Is pulse repetition period adjustable?
Yes
Pulse repetition period is _____ to period.
unrelated
Pulse repetition is related only to _____.
depth of view
Pulse repetition period is report in units of _____.
time
______ describes the max distance into the body that an ultrasound system is imaging.
Depth of view
Pulse repetition period and imaging depth are _______.
directly related
As depth of view increases, pulse repetition _____.
increases
As depth of view decreases, pulse repetition period _____.
decreases
With deeper imaging, the listening time and the oulse repetition period ______.
lengthen
With shallower imaging, the listening time and the pulse repetition period _____.
shorten
_______ is the number of pulses than an ultrasound system transmits into the body each second.
Pulse repetition frequency
Pulse repetition frequency is reported in units of _____.
Hertz or per second
Pulse repetition frequency is determined by _____.
sound source only
Pulse repetition frequency is determined by the _________ of the system.
maximum imaging depth
Is pulse repetition frequency adjustable?
Yes
Pulse repetition frequency and depth fo view are ______.
inversely related
As depth of view increases, pulse repetition frequency_____.
decreases
As depth of view decreases, pulse repetition period _____.
increases
Deep imaging occurs with a ______ pulse repetition frequency.
lower
Shallow imaging occurs with a _____ pulse repetition frequency.
higher
Pulse repetition period and pulse repetition frequency are ______.
inversely related
A longer pulse repetition period results in a _____ pulse repetition frequency.
lower
A shorter pulse repetition period results in a _____ pulse repetition frequency.
higher
______ is the percentage or fraction of time that the system transmits a pulse.
Duty factor
There are no ______ for duty factor.
units
Duty factor is determined by _____.
sound source only
Is duty factor adjustable?
Yes
Duty factor is ______ to imaging depth.
inversely related
Duty factor is _____ when the system id imaging as shallow depths.
higher
Duty factor is _____ when imaging at greater depths.
lower
Equation for duty factor is _____.
duty factor = pulse duration/ pulse rep. period x 100
These parameters: period, frequency, wavelength, and propagation speed describe both _____ and ____ wave sound.
pulsed; continuous