Doppler Review (Lesson 2)

Question 1

What is the Doppler Effect?

Answer 1

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

Question 2

What are the Doppler Effect factors known?

Answer 2

Relative motion of the reflector or source, motion direction, velocity of moving objects, angle, transmitting frequency, propagation speed of sound in a medium

Question 3

What is the Doppler Shift equation?

Answer 3

DS = Frequency Received - Frequency Transmitted
(DS = Fr - FT)

Question 4

If the transmitted frequency is 3 MHz and the received frequency is 2.98 MhZ, what is the doppler shift?

Answer 4

0.02 Mhz,
final answer is in KHz = -20 KHz

Question 5

What is the Doppler equation?

Answer 5

F (DS) = 2 Fo V
______
c

Question 6

Breakdown the Doppler shift equation; what does each component mean?

F (DS) = 2 Fo V
______
c

Answer 6

F(DS) - doppler shifted frequency
Fo - operating frequency
V - velocity of moving reflectors
C - speed of sound in soft tissue
2 - represents the round trip time

Question 7

What is the angle between the direction of blood flow and the sound progation direction called?

Answer 7

Insonification or Insonation angle.

Question 8

When Doppler angle increases, what happens to the Doppler shift frequency?

Answer 8

Decreases

Question 9

Is a doppler effect calculated when the Doppler angle is at 90, Cos 0 ?

Answer 9

No doppler effect, no motion towards or away from the transducer