RIU 324 Lecture Notes - Lecture 14: Grayscale, Color Field, Flow Velocity

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amethystbear941

29 Mar 2020

School

GVSU

Department

Radiation and Imaging - Ultrasound

Course

RIU 324

Professor

Angela Malone

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Document Summary

Doppler: facilitates placement of the sampling volume. 12. what is the power spectrum: spectral analysis shown in the frequency domain. 13. what is defined by the operator using the angle correct control: direction of flow. 14. why is the baseline positioned off-center: expand the velocity range in one direction. 15. what is the function of spectral invert: alter the direction assignment of the vertical axis, what is the purpose of doppler reject, removes low-amplitude signals from the spectral display. 17. what is the purpose of the wall filter: removes low-velocity reflectors from the spectral display. If the timing delay for gate activation is changed from 52 us to 48 us: sampling volume is at decreased depth. 25. eliminate aliasing a. increase velocity scale (prf), adjust baseline, increase angle of insonation, decrease depth to sample volume, switch to high-prf mode, switch to lower transmitted frequency, switch to cw. The overall approach to remove aliasing is to reduce the.

Related Questions

Doppler Effect When a car with its horn blowing drives by an observer, the pitch of the horn seems higher as it approaches and lower as it recedes (see the ﬁgure below). This phenomenon is called the Doppler Effect. If the sound source is moving at speed relative to the observer and if the speed of sound is, then the perceived frequency is related to the actual frequency as follows.

We choose the minus sign if the source is moving toward the observer and the plus sign if it is moving away. Suppose that a car drives at past a woman standing on the shoulder of a highway, blowing its horn, which has a frequency of 500 Hz. Assume that the speed of sound is . (This is the speed in dry air at .)

What are the frequencies of the sounds that the woman hears as the car approaches her and as it moves away from her?

sangriafish990

When a car with its horn blowing drives by an observer, the pitch of the horn seems higher as it approaches and lower as it recedes (see the figure). This phenomenon is called the Doppler effect. If the sound source is moving at speed relative to the observer and if the speed of sound is , then the perceived frequency f is related to the actual frequency as follows:

We choose the minus sign if the source is moving toward the observer and the plus sign if it is moving away.
Suppose that a car drives at 110 ft/s past a woman standing on the shoulder of a highway, blowing its horn, which has a frequency of 500 Hz. Assume that the speed of sound is 1130 ft/s.

(a) What are the frequencies of the sounds that the woman hears as the car approaches her and as it moves away from her?
(b) Let A be the amplitude of the sound. Find functions of the form

that model the perceived sound as the car approaches the woman and as it recedes.

fuchsiaelk214

RIU 324 Lecture Notes - Lecture 14: Grayscale, Color Field, Flow Velocity

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