Doppler- Effect

What is the audible Doppler range?

-10khz to +10khz

what is the cosine of angle 90?

0

what is the best angle for imaging?

0 , biggest doppler shift

what is the cosine of angle 0?

1

which transducer will have a higher doppler shift? 5Mhz 10Mhz

10Mhz

What angles should you stay between when scanning vessels

30-60

worst angle for doppler* imaging?

90, no doppler shift

What is used to find the max speed of blood flow?

Aliasing

The Doppler shift depends on the _____ of the doppler angle

Cosine

Relationship between Doppler shift and velocity of reflector (blood)

Direct

Cosine of angle measured between what?

Direction of blood flow and axis of beam

This is the difference between the emitted frequency and the echo frequency returning from moving scatterers

Doppler shift

Is an angle greater than 60 good for calculating flow speed ?

No , not reliable

Is an angle less than 30 good for calculating flow speed?

No , sound being totally reflected

If the ------ speed increases the Doppler shift increases

Scatterer and source

The Doppler shift occurs at the interface of each _____ change

Velocity

what is the determining factor in determining flow velocity?

angle of incidence

what is doppler effect?

change in frequency caused by motion of a sound source, receiver, or reflector

as doppler angle increases, the doppler shift _____

deceases

if cosine increases, the calculated scatterer speed ____

decreases

if source frequency increases,the scatterer speed _____

decreases

the doppler shift depends on the cosine of the ____ ____

doppler angle

blood flow and tissue motion are the sources of the ____ ____

doppler effect

the change of frequency caused by motion is called a _____ _____

doppler effect

doppler instruments measure what?

doppler shift

the doppler shift is proportional to _____ ____

flow speed

do higher or lower frequencies produce larger doppler shifts?

higher

if reflector is moving toward the source, then the echo has a _____ frequency

higher

if the doppler angle increases, the scatterer speed ___

increases

the larger the doppler angle, the ___ the doppler shift

less

if motion is away from source, the frequency of echo is _____

lower

for flow away from transducer, the doppler shift is ____

negative

is there a doppler shift if angle is perpendicular to flow?

no ,no doppler shift for 90 degrees

for flow word the transducer,the doppler shift is ____

postive

what does the "2" represent in the doppler equation?

result of 2 doppler shifts for a scatterer

doppler effect happens because of motion of 3 things:

source receiver reflector