Nature Of Sound Flashcards
Comes from the latin word ______ means “sound”
Sonus
Comes from a greek word ________ means “ to write or record”
Graphien
Other terms for sonography
Diagnostic ultrasound
Diagnostic medical sonography
Branch of physics that deals with sound and sound waves
Acoustics
Sound frequencies beyond upper limits of human hearing
Ultrasound
Were the first to describe the relationship bet pitch and frequency
Greeks
Pythagoras invented the ______ , to study musical sounds
Sonometer
Discovered the angle of reflection is equal to the angle of incidence
Leonardo da Vinci
Studies the actuvities of bats
Lazzaro Spallanzani
Theory of wave diffraction
Augustin Fresnel
Effect of motion on the pitch of sounds
Christian Johann Doppler
Studies the phenomenon of piezoelectricity
Jacques and Pierre Curie
Wrote the theory of sounds
Lord Rayleigh
Sound waves to detect underwater objects ( SONAR) Sound Navigation Ranging
Paul Langevin
The first contact compound B scanner used ________ as lubricant
Olive oil
Early ultrasound equipment visual displays used __________ that produced “bi-stable” (BW) images
Storage oscilloscope
Gray scale was introduced
1970
Real time scanning was introduced
Mid 1970s
Application of doppler technique
1980s
Travelling variation in one or more quantities such as pressure
Wave
Two categories of wave phenomena
Mechanical Wave
Electromagnetic wave
A type of wave that can only travel through matter
Mechanical
Can travel through matter or through empty space
Electromagnetic
Two basic types of wave
Longitudinal
Transverse
Motion of the particle in a medium is PARALLEL to the direction of wave propagation
Longitudinal wave
Motion of the particle in a medium is PERPEDICULAR to the direction of wave propagation
Transverse Wave
An energy transmitted as a mechanical , longitudinal wave that requires a medium through which to travel
Sound
Sound is a travelling variation of ______
Pressure and density
Regions of LOW pressure and density
Rarefactions
Regions of HIGH pressure and density
Compressions
Wave anatomy
Wavelength
Frequency
Period
Phase
Distance bet 2 consecutive identical positions of wave
Wavelength
Wavelength is represented by the sign of ________
Lambda
1 wavelength is equal to
1 cycle
No of cycles per second
Frequency
One complete oscillation of the wave
Cycle
Unit of frequency
Hertz
Latin word meaning “below”
Infra
The latin word meaning “ beyond”
Ultra
Below 20 Hz
Infrasound
the clarity of the image
Spatial Resolution
As frequency increases
Small objects improves
Penetrability decreases
More collimated and directional
Time it takes for one cycle to occur
Period
Period and frequency is _________
Inversely proportional
Realtionship of one wave to another
Phase
UTZ wave that are same position
In phase
Utz wave that are out of position
Out of phase
Demonstrates interference phenomena or the superimpostion of waves ( algebraic summation)
Sound waves
Interaction of two or more ultrasound beams
Interference
2 kinds of interference
Constructive
Destructive
UTZ waves are in phase . Increase in amplitude and intensity
Constructive interference
Utz waves are out of phase. Decrease in amplitude . Contributes to attenuation
Destructive interference
Had an insight on the nature of wave propagation
Christian Huygens
Every point on wave front may be considered a source of secondary spherical wavelets
Huygen’s Principle
Describes the production of ultrasound wavefront from individual wavelets
Huygen’s principle
Two sound waves w/ slightly different frequencies combined and has a pattern
Beats
The rate at which the beats occur
Beat frequency
Two waves travelling in the opposite directions w/ same amplitude
Standing Waves
Zero amplitude caused by destructive interference
Nodes
Maximum amplitude caused by constructive interference
Antinodes
2 types of utz waves in diagnostic equipments
Continuous wave
Pulsed
Cycles repeat indefinitely
for fetal heartbeat and blood flow in doppler method
Continuous Wave
Pulses separated by gaps in time
modes and real time imaging
Pulsed wave
Few cycles of ultrasound
Pulse
Pulsed ultrasound
Pulse Repetition Frequency Pulse Repetition Period Pulse Duration Duty Factor Spatial Pulse Length
No of pulses occurring in 1 sec
Pulse Repetition Frequency
Time from the beginning of one pulse to the next
Pulse Repetition Period
Time it takes for one pulse to occur
Pulse Duration
Fraction of time that pulsed ultrasound is on
Duty factor
Length of space that a pulse takes up
Spatial Pulse Length
Medical imaging that uses non ionizing , high frequency soundwaves
Sonography
