Lesson 18 (Part 3) Flashcards
1
Q
What can echoes arriving to the transducer be as well?
A
Delayed
- phasing
2
Q
What does delayed echoes allow?
A
- Reception steering
- Dynamic steering
- Dynamic aperture
3
Q
Reception steering
A
Listening from a particular direction
4
Q
Dynamic focusing
A
Continual change of the focus with increasing depth
- similar to camera focus
5
Q
Dynamic aperture
A
As the focus continues to change during echo reception, the aperture will increase to maintain a constant focal width
6
Q
Annular arrays
A
Concentric rings
- piezoelectric material carved out in rings
7
Q
What does the largest ring in annular arrays have?
A
The deepest focus
8
Q
Why is annular arrays not used anymore?
A
Because we can do the same thing with phasing
9
Q
What determines the beam width at the focus? (3)
A
- Aperture
- Focal length
- Wavelength
10
Q
In phasing, what happens to the reception beam? (2)
A
- It is steered
2. Dynamically focused
