Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHY > Beam former > Flashcards

Beam former Flashcards

1
Q

number of cycles per second is called?

A

Frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

number of pulses per second?

A

PRF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Number of pulses per scan line?

A

ensenble length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

ensemble length on dopper?

A

3-30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ensemble length on 2D?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

of cycles in a pulse on 2D and doppler?

A

2D- 2-3

Doppler- 5-30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what affects PRF in B-mode?

A

penetration/ depth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

grating lobes are produced by?

A

arrays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

3 ways to fix grating lobes?

A
  1. apodization
  2. THI
  3. subcidy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what affects NZL?

A
  • frequency

- aperture sizer/ diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

U/S systems are what kind of system?

A

pulse-echo systems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

u/s systems determine what?

A

strength and location of echo-generating site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

the location of an echo is determined by? (2)

A
  • arrival time (depth)

- direction of returning echoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

4 main sections of intrument?

A

1- beam former
2- signal processor
3. image processor
4. display

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what 8 things are involved in the beam former?

A

1) Master Synchronizer*
2) Pulser
3) Pulse delays
4) Transmit/Receive Switch
5) Amplifiers
6) Analog-to-Digital Converters
7) Echo delays
8) Summer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

beam former involves?

A
  • transmission and reception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what are transmission channels?

A
  • each path to each individual element is a channel
18
Q

what are reception channels?

A
  • each path from each individual element
19
Q

beam former- components of transmitter? (4)

A
  • master synchronizer
  • pulser
  • pulse delays
  • T/R switch
20
Q

beam former- components of receiver? (4)

A
  • amplifier (TGC, overall gain)
  • analog-to-digital converters
  • echo delays
  • summer
21
Q

what is the master synchronizer?

A
  • coordinated the entire system
  • tells pulser when to fire
  • T/R switch functions
22
Q

master synchronizer prevents?

A
  • range ambiguity (incorrect placement of echo along scan line)

AKA echo-misplacement

23
Q

what is the pulser?

A
  • produces electric voltages that drive the transducer
24
Q

operating frequency range?

A

from 2-20 MHz

25
Q

PRFvolt= PRFpulse what are the typical values for 2D?

A

4- 15 kHz

26
Q

PRF?

A
  • operator controlled in doppler
  • automatic in grey scale
  • depth of image will determine PRF
27
Q

PRF is limited by?

A

depth

28
Q

what is the pulser?

A
  • all echoes from one pulse must be received before the next pulse is emitted
29
Q

pulser- deeper images?

A
  • echoes take longer to return

- decreased PRF and FR and Temp. res

30
Q

Beam former- What happens if we go over 77 cm/ms?

A
  • range ambiguity
31
Q

What happens to the PRF in 2D if depth is increased by 4 x?

A
  • PRF must drop 4x to prevent range ambiguity
32
Q

Pulser can be controlled in terms of?

A

power output

33
Q

transmission channels typically there are how many?

A

64, 128, 192

34
Q

Pulse delays?

A
  • involved in sequencing arrays

- multiple blocks of sound, each producing a scan line

35
Q

what instument of the beam former is involved in phasing?

A

pulse delays

36
Q

how much time is between element firings?

A

< 1 microsecond delays between element firings

37
Q

what can pulse delays affect?

A

Can affect our near zone length (natural focus)
Can affect our beam width at the focus
How does this affect our image?
Lateral resolution

38
Q

pulse delays are involved in?

A
  • dynamic aperture control
  • apodization
  • coded excitation
38
Q

pulse delays are involved in?

A
  • dynamic aperture control
  • apodization
  • coded excitation
39
Q

dynamic aperture control ?

A

pulser + pulse delays

  • decided the width of our aperture
40
Q

apodization?

A

Decreasing the strength to outer elements

Reduction of grating lobes in arrays

41
Q

Coded excitation allows for? (5)

A 
multiple foci
spatial compounding
increased penetration
↑ contrast resolution
B-flow imaging

PHY (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions