Module 5: Review Questions

Question 1

Identify all the factors you can think of which will have a Bering on the lined density of the image?

Answer 1

1. Depth
2. Sector
3. Width
4. Number of focuses

Question 2

A transducer with a focal length of 5 would be considered to be _______ focused?

Answer 2

Moderately

Question 3

What is sub dicing? And of what value is it?

Answer 3

Single element cut into small pieces to reduce grating lobes

Question 4

Why are more channels better than fewer channels? Or are they?

Answer 4

More channels = more scan lines = better spatial resolution

Question 5

Describe how “dynamic damping” is accomplished and why is it useful?

Answer 5

Electronic. Allows probes to be multi functioning

Question 6

What is cross talk?

Answer 6

One crystal vibrates and affects the adjacent ones

Question 7

Is cross talk controlled? And if so how?

Answer 7

Air between the crystals and Apodization

Question 8

Explain the difference between interpolation and overwriting?

Answer 8

Interpolation fills in missing data and overwriting data

Question 9

What is receive focus and why is it necessary?

Answer 9

Getting the returning echoes to add in phase so you don’t lose information

Question 10

What is the refresh rate for a frozen image on a CRT?

Answer 10

1/30

Question 11

What is the result if the lines per frame multiplied by the depth and the number of foci is greater than 77,000?

Answer 11

Range ambiguity

Question 12

Which term describes the averaging of echo data due to an increased line density?

Answer 12

Overwriting

Question 13

Which of the following is a consideration when increasing the scan line density?

1. Overwriting
2. Interpolation
3. Extrapolation
4. Frame averaging

Answer 13

Overwriting

Question 14

What dimension are the sub elements cut to help eliminate grating lobes?

Answer 14

Less than a wavelength

Question 15

As the time to create one frame increases what happens to the frame rate?

Answer 15

It decreases

Question 16

At what rate will the average human detect flicker on a display?

Answer 16

15-20 fps

Question 17

Increasing the depth of field will negatively impact the frame rate? T/F?

Answer 17

True

Question 18

Which of the following can be used to improve scan line density?

1. Use read zoom
2. Add a focal zone
3. Decrease the sector angle
4. Increase edge enhancement

Answer 18

Decrease sector angle

Question 19

In addition to Apodization, what other manufacturing process is used to reduce the impact of grating lobes?

Answer 19

Sub Dicing