Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
36 Cards in this Set
- Front
- Back
|
QUALITY FACTOR=Is the operating freq. divided by the bandwidth
|
Q=fo/Bw
unitless Is the operating freq. divided by the bandwidth |
|
|
AXIAL RESOLUTION=Is the minimum reflector separation required along the direction of sound travel to produce separate echoes.
|
RA=SPL/2 or RA=.77*N/F
RA=mm |
|
|
LATERAL RESOLUTION=Is the minimum reflector separation in the direction perpendicular to the beam direction that can produce 2 echoes
|
LA=DB
LA=mm DB=beam width |
|
|
Artifacts know all four
|
1. not real 2. missing
3. improperly located 4. Of improper brightness, shape, or size |
|
|
NYQUIST LIMITS=Aliasing occurs when the Doppler shift exceeds the Nyquist limit
|
NYQUIST=PRF/2
|
|
|
Axial Resolution is also know as
|
longitudinal
range depth |
|
|
Lateral Resolution is also know as
|
transverse
angular azimuthal |
|
|
NEAR ZONE IS ALSO KNOWN AS
|
NEAR ZONE
NEAR FIELD NEAR FIELD |
|
|
FAR ZONE IS ALSO KNOWN AS
|
FAR ZONE
FAR FIELD FRAUNHOFER ZONE |
|
|
OPERATING FREQUENCY
ALSO KNOWN AS |
RESONANCE FREQUENCY
|
|
|
ACOUSTIC VARIABLES
|
PARTICLE MOTION OR VIBRATION
TEMPERATURE DENSITY PRESSURE |
|
|
SUBSONIC OR INFRASOUND
|
1-20Hz
|
|
|
RANGE AMBIGUITY
|
Penetration(cm)x # of focuses x lines per frame x frame rate≤77,000
|
|
|
RANGE OF ULTRASOUND=Artifacts places structures much closer to the surface than they should be.
|
GREATER THAN 20kHz
|
|
|
Spatial & temporal considerations
|
SATA= LOWEST VALUE
SPTP= HIGHEST VALUE |
|
|
RANGE OF ULTRASOUND
|
GREATER THAN 20kHz
|
|
|
PERIOD=Time for one cycle to occur
|
T=1/F
μs microseconds |
|
|
WAVELENGTH=Is the length of space over which one cycle occurs
|
ﻼ=C/F
ﻼ=mm C= μs/mm f=MHz |
|
|
PULSE DURATION= Is the time that it takes 1 pulse to occur
|
PD=T * N
SPL= mm ﻼ=MHz |
|
|
SPATIAL PULSE LENGTH= Is the length of pulse from front to back
|
SPL=ﻼ * N
SPL= mm ﻼ=MHz |
|
|
PULSE REPITITION PERIOD= Is the time from the beginning of 1cycle to the beg. Of the next
|
PRP=1/PRF
PRP=μs PRF=kHz |
|
|
IMPEDANCE= Describes the relationship between acoustic pressure & the speed of particle vibrations in a sound wave
|
=P * C
= RAYLS P=Kg/m³ C= m/s |
|
|
ATTENUATION= Loss of amplitude & intensity as sound travels thru a medium
|
A=F/2 * L
dB |
|
|
ATTENUATION COEFFICIENT= Attenuation occur in each cm the sound wave travels
|
A=F/2
dB/cm² |
|
|
AMPLITUDE= Maximum variation that occurs in an acoustic variable
|
AMPLITUDE=
MAXIMUM VARIATION – NORMAL VALUE |
|
|
INTENSITY= Is the rate at which energy passes through a unit area
|
I=P/A
I= W/CM P=W A=CM |
|
|
INTENSITY PROPORTION=
If amplitude is doubled intensity is quadrupled. If amp. is halved intensity is quartered |
I=A²
I=W/CM A=CM² |
|
|
PERPINDICULAR INCIDENCE=
Denotes a direction of travel of the u/s wave perpendicular to the boundary between 2 media. |
IRC=[2-1] or IRC=IR/II
2+1 W/CM² |
|
|
Perpindicular incidence
Transmitted intensity coefficient |
ITC=1-IRC
W/CM² |
|
|
OBLIQUE INCIDENCE= Denotes a direction of travel time of the incident u/s that is not perpendicular to the boundary between 2 media
|
Өt=Өi * C2/C1
UNITS ARE IN ANGLES OR DEGREES |
|
|
OBLIQUE INCID. When no refraction
|
Өi=Өr
|
|
|
RANGE= Distance from the transducer to an echo generating structure
|
d=C/2 * t
d=mm C=mm/μs t= roundtrip travel time |
|
|
RANGE
|
d=.77 * t
mm |
|
|
RANGE
|
d=t/13
cm |
|
|
OPERATING FREQUENCY= Is the preferred or natural frequency of operation for the element
|
fo=CM/2 * W
Fo=MHz CM=prop. Sp. of trans. ele. W= trans. thkness |
|
|
NEAR-ZONE LENGTH= The region extending from the element out to a distance of 1 near-zone length
|
NZL=DT²/4 *ﻼ OR NZL=DT²*f/6
NZL=mm DT²=mm ﻼ=mm |
