Types of Transducers and Electronic Phasing

Question 1

What is known as a group of elements or crystals?

Answer 1

Array

Question 2

What is known as applying voltage pulses to a group of elements in succession?

Answer 2

Sequencing

Question 3

What type of transducer produces a rectangle image?

Answer 3

Linear sequenced array

Question 4

What is the process of exciting crystals by small time differences?

Answer 4

Phasing

Question 5

What is a vector array also called?

Answer 5

Trapezoidal scanning

Question 6

In trapezoidal scanning, what portion of the beam is scanned via sequencing and phasing?

Answer 6

Sequencing = in the middle of the beam

Phasing = the “wings”

Question 7

What is the term used for crystal excitation by small time differences?

Answer 7

Phasing / electronic steering

Question 8

When phasing from L to R, where will the image appear?

Answer 8

Right

Question 9

When phasing from R to L, where will the image appear?

Answer 9

Left

Question 10

What transducer has the most number of scan lines?

Answer 10

Convex array / curvilinear probe

Question 11

In a linear array transducer, the width of the whole image is equal to what?

Answer 11

The length of the array

Question 12

What happens to the curvature and focus when there are GREATER time delays?

Answer 12

Greater curvature puts the focus more shallow

Question 13

What happens to the curvature and focus when there are SMALLER time delays?

Answer 13

Smaller curvature puts the focus deeper

Question 14

With a smaller NZL, will the focus be more shallow of deep?

Answer 14

More shallow

Question 15

Will a shorter aperture create a shorter or longer NZL?

Answer 15

Shallow/shorter NZL

Question 16

To maintain the same beam width at the focus for increasing focal lengths, what must happen to the aperture?

Answer 16

Increase

Question 17

What type of artifact is seen when there are additional weaker beams resulting from multi-element array transducers?

Answer 17

Grating lobes/side lobes

Question 18

What can help to reduce grating lobes?

Answer 18

Apodization

Question 19

What is apodization?

Answer 19

Drives elements with different voltages across the aperture

Question 20

Which imaging format must do a combination of sequencing and phasing in order to operate?

Answer 20

Vector

Question 21

What advantages can be gained from the ability to steer beams in linear array transducer? (Lecture 5)

A) CD applications

B) Harmonic Imaging

C) Wider fields of view via trapezoidal image formats

D) All of the above

E) A and C

Answer 21

E) A and C