2.6 Data Representation
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What is Denary?
It is the decimal number system that we are used to
What is Binary?
0 and 1’s.
What is the purpose of Hexadecimal numbers?
Provide a human-friendly representation of binary-coded values
What is an Overflow error?
When the total amount does not fit in 8 bits
What is the effect of a binary shift to the left?
Multiplies the number by 2
What is the effect of a binary shift to the right?
Divides the number by 2
What are Character sets?
A table of data that links a character to a number
What is ASCII?
Is a character encoding standard for electronic communication
How many bits are in each character of ASCII?
Each character is represented by a 7-bit number
How many bits are in each character of extended ASCII?
Each character is represented by an 8-bit binary number
How many bits are represented in each letter of Unicode?
Each letter is represented by a 16-bit
What are the benefits of using Unicode?
This gives at least twice as many character options as ASCII Allows the character set to represent characters and symbols from all languages.
What are images made up of?
Images are made up of pixels
What is the color of a pixel represented by?
A binary number
How many colors will there be in an image which uses 1 bit?
2 colors
How many colors will there be if an image uses 2 bits for each color?
4 colors
What is color depth?
The number of bits used for each pixel
What is Resolution?
How many pixels are in a certain space
What is the effect of increasing the resolution of an image?
It increases the image quality Increase file-size
What is Metadata?
The information about the image file that is stored within it
What are 3 examples of Metadata?
Height Width Color depth Resolution File format Data and time of the creation
What is the purpose of sampling?
Allows analogue signals to be converted into digital signals so that it can be stored on a computer
How does sampling work?
The amplitude of the wave is measured at regular intervals which creates a digital representation More samples would lead to a more accurate sound file but leads to a larger file size
Why is compression used?
Used to make the file-size smaller