Character Sets
What is a character set?
- All characters and symbols that the computer recognises/uses
- A list of characters recognised by the computer hardware and software
- Each character and symbol has a unique value
Unicode vs ASCII
- UNICODE has greater range of characters than ASCII
- UNICODE represents most written languages in the world while ASCII does not — ASCII used for English only
- UNICODE can represent emojis, ASCII does not
- ASCII uses 7 or 8 bits per character whereas UNICODE uses 16/32 bits per character
- UNICODE has 60/4 billion characters, ASCII has 128/256 characters
Advantage of using Unicode instead of ASCII
- It can represent more characters
- It can represent emojis/symbols
- It can represent more languages
Disadvantage of using Unicode instead of ASCII
- Each character requires more storage space
Describe how text is converted to binary
- A character set is used
- …such as ASCII/UNICODE
- Each character has a unique binary value
Explain how the word "RED" is represented using a character set
Unique binary/denary number given for each character
The code for R is stored, then the code for E then D in sequence
Sound
Sound Definitions
- Sample rate: the number of samples taken per second
- Sample resolution: the number of bits per sample
- Pixel: One square/circle of one colour // the smallest component of the image
How does a computer represent sound?
- A sound wave is sampled for sound to be converted to binary, which is processed by a computer
How does a computer represent sound? (NEW)
- Recorded using a microphone
- Sound wave is sampled…
- …measuring the height/amplitude
- Each amplitude has a unique binary value
- The sample rate is set
- …that is the number of samples taken per second
- The sample resolution is set
- …that is the number of bits used for each sample
- Each sample taken is converted to binary
What happens if the sample rate/sample resolution is increased?
- The file size will increase
- The accuracy of the recording will increase
- Larger dynamic range
- Will take a longer time to download/upload
Images
Image Definitions
- Resolution: the number of pixels in an image
- Colour depth: the number of bits used to represent each colour
- Pixel: smallest component of the image
How does a computer represent images?
- An image is a series of pixels that are converted to binary which can be processed by a computer
What happens if the colour depth/resolution is increased?
- The file size will increase
- The quality of the image will be increased
- Will take a longer time to download/upload