1.2 Text, sound and images

By the end of this section you should be able to

• 1.2.1 Explain how and why text is stored using character sets, including ASCII and Unicode
• 1.2.2 Explain how and why sound is stored, including the effect of sample rate and sample resolution
• 1.2.3 Explain how and why images are stored, including the effect of resolution and colour depth

Lessons

1. Character sets
2. Sound
3. Images

Key vocabulary

Character set

All the characters a computer can represent, each with its own binary code.

ASCII

A character set that uses 7 or 8 bits per character, mainly for English text.

Unicode

A character set with far more characters than ASCII, including other languages and emojis; it uses more bits per character.

Sample rate

The number of sound samples taken each second.

Sample resolution

The number of bits used to store each sound sample.

Pixel

The smallest single point of colour in a digital image.

Image resolution

The number of pixels in an image.

Colour depth

The number of bits used to represent the colour of each pixel.