Memory and Display

Question 1

what does the memory allow us to store

Answer 1

the image

Question 2

what is memory responsible for

Answer 2

grayscale

Question 3

memory enables what

Answer 3

freeze frame
cine-loop
the ability to post-process the image

Question 4

what is another name for the memory

Answer 4

scan converter

Question 5

what is designed to store ultrasound information and what does it enable the machine to do

Answer 5

modules or circuits

enables the machine to build up the image

Question 6

from the memory where does the image go to

Answer 6

a display or recording device

Question 7

historically scan conversion was what kind of process

Answer 7

analog

Question 8

current systems use what kind of scan converter

Answer 8

digital

Question 9

what is the difference between analog and digital scan converters

Answer 9

analog: stores voltages
digital: stores binary code

Question 10

analog memory is

Answer 10

continuous values
prone to drift
less reproducible

Question 11

digital memory is

Answer 11

discrete numbers
stable
reproducible

Question 12

an analog scan converters’ charge is proportional to what

Answer 12

the amplitude of signal strengths

Question 13

main advantage of the analog scan converter

Answer 13

allows for grey scale

Question 14

analog scan converter also acts a what between the image and display

Answer 14

buffer

Question 15

does the analog scan converter have a good short term memory

Answer 15

yes

Question 16

what is the disadvantage of the analog scan converter

Answer 16

prone to drift

no long term memory

Question 17

this type of scan converter is reliable and vestile

Answer 17

digital

Question 18

digital scan conveters can be connected to what

Answer 18

many other systems or cameras

Question 19

does the digital scan converter have superior resolution

Answer 19

yes

Question 20

a digtial scan converter consists of what

Answer 20

a matrix

Question 21

a digital scan converters matrix is typically

Answer 21

1024 x 768

Question 22

the matrix is divided into small rectangular squares picture elements called

Answer 22

pixels

Question 23

each pixel contains a

Answer 23

digital number

Question 24

each digital number represents

Answer 24

the amplitude of the received echo

Question 25

a 1024 x 768 matrix has how many pixels

Answer 25

786432

Question 26

the matrix is essentially

Answer 26

a checkerboard arrangement of pixel locations on a gird

Question 27

each square of the matrix does what

Answer 27

stores data that represents the greyscale information of the returning echoes

Question 28

the monitor should be thought as

Answer 28

the matrix with each square corresponding to a particular depth

Question 29

computers operate in

Answer 29

binary code

Question 30

binary is the language that only uses what

Answer 30

1's and 0's

Question 31

that data contained within each square of the matrix is equal to what

Answer 31

a one or zero

Question 32

how many shades of grey can be displayed then

Answer 32

256

Question 33

in order to get severak shades of grey

Answer 33

additional matrices must be stacked one on top of another so that every pixel location can be represented by several ones and zeros

Question 34

the combination of the binary digit can represent what

Answer 34

many shades of grey

Question 35

a pixel is

Answer 35

a picture element and is the smallest form of display

Question 36

more pixels means what

Answer 36

better resolution

Question 37

one binary digit is called a

Answer 37

bit

Question 38

a Bit is either a

Answer 38

1 or 0

Question 39

8 bits of data is a

Answer 39

byte

Question 40

word

Answer 40

combination of bits expressed as a unit

Question 41

word length

Answer 41

number of bits in a word

Question 42

bit depth

Answer 42

the word length at each address location

Question 43

RAM

Answer 43

random access memory | fast,rewritable,cheap and erased when machine is turned off

Question 44

ROM

Answer 44

read only memory | permanent and used for system funtions

Question 45

the formula for calculating the shades of grey is

Answer 45

2^n

Question 46

as bit depth increases

Answer 46

the shades of gray that the system can produce increases

Question 47

what does n represent

Answer 47

the bit depth or the number of bits used at each adress location to store the echo data received

Question 48

typically ultrasound machines have how many bits

Answer 48

8

Question 49

a bit depth of 8 has how many shades of grey

Answer 49

256

Question 50

the binary system relies on a how many digits

Answer 50

2

Question 51

1 or 0 represent a

Answer 51

circuit that is either on or off

Question 52

the computer only has to process 2 numbers so is this process fast and very stable

Answer 52

yes

Question 53

ultrasound systems operate to provide

Answer 53

the best resolution images but this is limited by the type of display used

Question 54

the two considerations made for monitor resolution are

Answer 54

number of pixels | size of the pixels

Question 55

more pixels in a finite space

Answer 55

the better the resolution will be

Question 56

why will the resolution be better if there is more pixels

Answer 56

because the size of the pixels must decrease to fit the monitor

Question 57

changing the depth of the field also will impact the

Answer 57

resolution

Question 58

modern day ultrasound units use what kind of monitor for display

Answer 58

LCD

Question 59

earlier units used what kind of unit for display

Answer 59

CRT

Question 60

A-mode and B-mode used what kind of unit for display

Answer 60

oscilloscope

Question 61

the oscilloscope was the first to use what

Answer 61

CRT

Question 62

an oscilloscope can only display

Answer 62

the x and y axis and is not compatible with a video signal

Question 63

television CRT accept what kind of signal

Answer 63

video

Question 64

a television CRT is capable of what

Answer 64

displaying a wide range of grays

Question 65

if equipped the CRT is also capable of what

Answer 65

displaying colour, this is helpful for doppler applications

Question 66

CRT

Answer 66

large glass vacuum tube that contains a cathode or source of electrons

Question 67

the electron beam is aimed at what

Answer 67

a positive phosphor plate

Question 68

electrical or magnetic deflections plates are used to

Answer 68

steer the beam

Question 69

the brightness of the phosphor brightness depends on

Answer 69

the number of electrons that it strikes

Question 70

number of electrons is dependent on

Answer 70

the amplitude of the video signal

Question 71

to obtain colour how many electron guns are fired

Answer 71

three

Question 72

what do the three electron guns cause the phosphor to light up to ehich colours

Answer 72

red green blue

Question 73

different mixes of these colours produce

Answer 73

all the colours that are seen when watching tv

Question 74

raster format

Answer 74

a specific method to move the electron beam

Question 75

the beam moves in which direction

Answer 75

left to right

Question 76

interlacing

Answer 76

writes the even and than odd lines of scan data

Question 77

a complete CRT frame consist of how many horizontal lines

Answer 77

525

Question 78

1 frame rate is

Answer 78

30 Hz

Question 79

each frame has two fields produced at

Answer 79

60 Hz

Question 80

computer mointors are superior to CRT in which way

Answer 80

have more scan lines and pixels | as well the pixels are smaller

Question 81

more pixels mean

Answer 81

higher resolution

Question 82

monitors use how many scan lines

Answer 82

1024 x 768 or higher

Question 83

the scan lines are written in what kind of manner

Answer 83

progressive manner with frame rates typically higher than 60Hz