Topic 3 -Fundamentals of Data Representation Flashcards
What is denary?
0 - infinite
What is binary?
0’s and 1’s
What does a left binary shift do?
x2
What does a right binary shift do?
Divide 2
0 + 0 =
0
0 + 1 =
1
1 + 1 =
0 carry 1
1 + 1 + 1=
1 carry 1
1 + 1 + 1 + 1=
0 carry 1 two spaces
What is hexadecimal?
0 -9
A = 10
B = 11
C=12
D = 13
E =14
F = 15
What is ASCII?
A character set that uses 7 bits to represent numbers, symbols and characters
What is a disadvantage of ASCII?
Only in one language
What is unicode?
A character set based of ASCII for backwards compatibility that represents all major languages.
Uses 16 bits
What is resolution?
Total number of pixels
What is a pixel?
The smallest element of an image
What is a bitmap?
A grid arrangement of pixels
What is colour depth?
The number of bits needed to store all the colours
What is the formula for representation size?
Representation size = no. of pixels x colour depth
What is metadata?
Data about data
What happens if you enlarge a bitmap?
It becomes pixelated
What are vector graphics?
Images that never become pixelated because they are redrawn to size.
Eg. logos
What is amplitude?
The ‘height’ of the sound wave
What is sampling?
Taking a reading at regular intervals
What is sample rate?
The number of samples per second
What is sample rate measure in?
Hertz
What is sample size/ resolution?
The number of bits per sample
What is the formula for representation size?
Sample rate x sample size x duration
What does compression do?
Makes files smaller therefore reducing storage space
What is lossy compression?
When you remove unimportant data that can never be restored
What is lossless compression?
When you restore data it is the same as original
What is run-length-encoding?
Grouping repeated data
How do Huffman trees work?
They calculate the frequency of characters and create a binary tree
What does the left side of a Huffman tree represent?
0
What does the right side of a Huffman tree represent?
1
