SPI Review
What is frequency determined by? - ANSThe source, thickness of piezoelectric element and
propagation speed to a lesser degree
Thicker element is equal to ________ frequencies - ANSLower
What is the reciprocal of frequency and what is the symbol - ANSPeriod, T
The time it takes for 1 cycle to occur - ANSPeriod
What is propagation speed determined by - ANSStiffness and density of the medium
Propagation speed of sound through soft tissue - ANS1,540 m/s
Increasing the stiffness of a tissue does what to the propagation speed? - ANSIncreases
Increasing the density of a tissue does what to the propagation speed? - ANSDecreases
Propagation speed of tissues from slowest to fastest - ANSAir, fat, water, liver, blood,
muscle, bone
What is the distance over which one cycle occurs? - ANSWavelength
What happens to frequency when you increase the wavelength? - ANSDecreases
What is the wavelength symbol - ANSLambda
What is the wavelength equation? - ANSPropagation speed divided by the frequency
Units of wavelength - ANSMm, m, km
What is wavelength determined by? - ANSSource and medium
What describes the strength of the sound wave? - ANSAmplitude
What happens to a beam as it travels? - ANSDecreases in amplitude and intensity due to
attenuation
What does amplitude represent on the chart of a wave? - ANSThe height of a vibration
What does pascals measure? - ANSPressure amplitude
What happens to amplitude when you increase depth? - ANSDecreases due to attenuation
, What is amplitude determined by? - ANSThe source
Related to strength of the beam - ANSPower
What is the unit for power? - ANSWatts
What is power proportional to? - ANSAmplitude squared
Relates to strength of beam and represents the concentration of energy in beam -
ANSIntensity
What is the equation and unit for intensity - ANSPower/area, W/cm squared
What is acoustic resistance to sound in a medium? - ANSImpedance
What is the equation for impedance? - ANSDensity times propagation speed
What is impedance determined by and what are the units? - ANSThe medium, rayls
The bigger the mismatch, the stronger - ANSThe reflection and brighter the dot
What is the number of pulses that occur in one second? - ANSPulse repetition frequency
What is the unit of PRF? - ANSHertz
How is the PRF changed? - ANSBy changing depth
What would decrease the PRF? - ANSIncreasing depth
What is the reciprocal of of pulse repitition frequency? - ANSPulse repetition period
What is the time it takes for one pulse to occur? - ANSPulse repetition period
What is the pulse repetition period determined by? - ANSThe source
Measured from beginning of one pulse to beginning of the next including dead time -
ANSPulse repetition period
The time it takes for ONE pulse to occur - ANSPulse duration
What happens to the pulse duration if you increase frequency? - ANSDecreases
What happens to pulse duration if period is increased? - ANSIncreases
What is a percentage of time the sound is actually on? - ANSDuty factory or duty cycle
What is the equation for duty factor? - ANSPulse duration/pulse repetition period
What is frequency determined by? - ANSThe source, thickness of piezoelectric element and
propagation speed to a lesser degree
Thicker element is equal to ________ frequencies - ANSLower
What is the reciprocal of frequency and what is the symbol - ANSPeriod, T
The time it takes for 1 cycle to occur - ANSPeriod
What is propagation speed determined by - ANSStiffness and density of the medium
Propagation speed of sound through soft tissue - ANS1,540 m/s
Increasing the stiffness of a tissue does what to the propagation speed? - ANSIncreases
Increasing the density of a tissue does what to the propagation speed? - ANSDecreases
Propagation speed of tissues from slowest to fastest - ANSAir, fat, water, liver, blood,
muscle, bone
What is the distance over which one cycle occurs? - ANSWavelength
What happens to frequency when you increase the wavelength? - ANSDecreases
What is the wavelength symbol - ANSLambda
What is the wavelength equation? - ANSPropagation speed divided by the frequency
Units of wavelength - ANSMm, m, km
What is wavelength determined by? - ANSSource and medium
What describes the strength of the sound wave? - ANSAmplitude
What happens to a beam as it travels? - ANSDecreases in amplitude and intensity due to
attenuation
What does amplitude represent on the chart of a wave? - ANSThe height of a vibration
What does pascals measure? - ANSPressure amplitude
What happens to amplitude when you increase depth? - ANSDecreases due to attenuation
, What is amplitude determined by? - ANSThe source
Related to strength of the beam - ANSPower
What is the unit for power? - ANSWatts
What is power proportional to? - ANSAmplitude squared
Relates to strength of beam and represents the concentration of energy in beam -
ANSIntensity
What is the equation and unit for intensity - ANSPower/area, W/cm squared
What is acoustic resistance to sound in a medium? - ANSImpedance
What is the equation for impedance? - ANSDensity times propagation speed
What is impedance determined by and what are the units? - ANSThe medium, rayls
The bigger the mismatch, the stronger - ANSThe reflection and brighter the dot
What is the number of pulses that occur in one second? - ANSPulse repetition frequency
What is the unit of PRF? - ANSHertz
How is the PRF changed? - ANSBy changing depth
What would decrease the PRF? - ANSIncreasing depth
What is the reciprocal of of pulse repitition frequency? - ANSPulse repetition period
What is the time it takes for one pulse to occur? - ANSPulse repetition period
What is the pulse repetition period determined by? - ANSThe source
Measured from beginning of one pulse to beginning of the next including dead time -
ANSPulse repetition period
The time it takes for ONE pulse to occur - ANSPulse duration
What happens to the pulse duration if you increase frequency? - ANSDecreases
What happens to pulse duration if period is increased? - ANSIncreases
What is a percentage of time the sound is actually on? - ANSDuty factory or duty cycle
What is the equation for duty factor? - ANSPulse duration/pulse repetition period
