1 Ch 3: Describing Sound Waves Flashcards
The source of the sound wave is the…
ultrasound system and transducer.
The medium is the…
tissues through which the sound is traveling.
Period is the…
time it takes a wave to vibrate a single cycle; the timefrom the start of one cycle to the start of the next cycle.
Period is reported in units of…
time, such as microseconds, seconds, hours, or days.
The typical value of period in diagnostic u/s is…
.06 to .5 microseconds.
Period is determined by…
the sound source only, not by the medium.
Is period adjustable by the sonographer?
No.
Frequency is…
the number of particular events that occur in a specific duration of time. In u/s, the # of cycles per second.
Frequency is reported in units of…
per second, 1/second, hertz, or Hz.
In clinical imaging, the typical frequency range is…
from approximately 2 MHz to 15 MHz.
Frequency is determined by…
the sound source only.
Is frequency adjustable by the sonographer?
No.
Sound is described as infrasonic if its frequency is…
less than 20 Hz.
Sound is described as audible if its frequency is…
between 20 Hz and 20,000 Hz.
Sound is described as ultrasonic if its frequency is…
higher than 20,000 Hz (20 kHz).
How are period and frequency related to each other?
Inversely. As one increases, the other decreases.
Period and frequency have a special inverse relationship called…
reciprocal. If multiplied together, the result is one.
Amplitude is…
the ‘bigness’ of a wave; the difference between the maximum (or minimum) value and the baseline value.
Amplitude is reported in units of…
pressure (pascals or Pa), density (g/cm^3), particle motion (any distance), or decibels (dB).
In clinical imaging, typical amplitude ranges from…
1 million pascals to 3 million pascals.
Amplitude is determined by the…
sound source (though it does decrease as the wave travels through the body).
Is amplitude adjustable by the sonographer?
Yes.
Peak-to-peak amplitude is…
the difference between the maximum and minimum values (not just between one extreme and the baseline).
Power is the…
rate of energy transfer; the rate at which work is performed.