Doppler ultrasound is based on the shift of frequency in an ultrasound wave caused by a moving reflector, such as blood cells in the vasculature. Suppose that a stationary transducer (both speaker and microphone) directs ultrasounds of frequency 5 MHz toward a wall of blood cells ("Roll Tide!") moving toward the transducer with a speed of 0.50 m/s. The speed of sound in blood is assumed to be similar to water Vsound = 1500 m/s. I) Treat the blood moving toward the source as a moving observer (with positive velocity) and apply the Doppler shift equation to find the frequency of the ultrasound observed by the moving blood wall. (see Eq. 16-8 and keep lots of sig. figs.!) Hz foi = fal ¹+ 1

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Could you help me with number 6 please
6. Doppler Echocardiography - Double Doppler Shift:
Doppler ultrasound is based on the shift of frequency
in an ultrasound wave caused by a moving reflector,
such as blood cells in the vasculature.
Blood moving towards transducer
produces higher frequency echoes.
Suppose that a stationary transducer (both speaker and
microphone) directs ultrasounds of frequency 5 MHz
toward a wall of blood cells ("Roll Tide!") moving
toward the transducer with a speed of 0.50 m/s. The
speed of sound in blood is assumed to be similar to
water Vsound = 1500 m/s.
-
Blood moving away from transducer
produces lower frequency echoes.
I) Treat the blood moving toward the source as a
moving observer (with positive velocity) and apply
the Doppler shift equation to find the frequency of the
ultrasound observed by the moving blood wall. (see
Eq. 16-8 and keep lots of sig. figs.!)
noi
1+
Hz
for = fsl
1
batubigien
II) Treat the blood as a source of reflected sound, emitting frequency fs 11 = for moving toward the
transducer - now the observer (microphone). Calculate the frequency heard in the reflection.
(Keep lots of sig. figs.)
1
Hz
foul = fsu
III) Though the ultrasound frequencies (5 MHz) are far above the audible range, the Doppler
frequency shifts for moving blood occur in the audible range. It is both customary and
convenient to convert these frequency shifts into an audible signal through a loudspeaker that can
be heard by the sonographer to aid in positioning and to assist in diagnosis.
Calculate the beat frequency between the frequency emitted by the transducer (initial source) and
the Double-Doppler-boosted reflected frequency detected by the transducer (final observer).
fbeat = foll-fs1 =
Hz
Is this an audible frequency for the clinician to hear?
Yes/No
Transcribed Image Text:6. Doppler Echocardiography - Double Doppler Shift: Doppler ultrasound is based on the shift of frequency in an ultrasound wave caused by a moving reflector, such as blood cells in the vasculature. Blood moving towards transducer produces higher frequency echoes. Suppose that a stationary transducer (both speaker and microphone) directs ultrasounds of frequency 5 MHz toward a wall of blood cells ("Roll Tide!") moving toward the transducer with a speed of 0.50 m/s. The speed of sound in blood is assumed to be similar to water Vsound = 1500 m/s. - Blood moving away from transducer produces lower frequency echoes. I) Treat the blood moving toward the source as a moving observer (with positive velocity) and apply the Doppler shift equation to find the frequency of the ultrasound observed by the moving blood wall. (see Eq. 16-8 and keep lots of sig. figs.!) noi 1+ Hz for = fsl 1 batubigien II) Treat the blood as a source of reflected sound, emitting frequency fs 11 = for moving toward the transducer - now the observer (microphone). Calculate the frequency heard in the reflection. (Keep lots of sig. figs.) 1 Hz foul = fsu III) Though the ultrasound frequencies (5 MHz) are far above the audible range, the Doppler frequency shifts for moving blood occur in the audible range. It is both customary and convenient to convert these frequency shifts into an audible signal through a loudspeaker that can be heard by the sonographer to aid in positioning and to assist in diagnosis. Calculate the beat frequency between the frequency emitted by the transducer (initial source) and the Double-Doppler-boosted reflected frequency detected by the transducer (final observer). fbeat = foll-fs1 = Hz Is this an audible frequency for the clinician to hear? Yes/No
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