1.2 Text sound and images

How is text converted from analogue to digital?

Character set is used such as ASCII or binary

Each character has its own unique binary value

Unicode vs ASCII

Unicode has a greater range of unique characters and symbols like different languages and emojis

ASCII has fewer characters

ASCII covers limited set of languages

ASCII requires 7/8 bits per character, Unicode has 16/32 bits per character

How does a computer represent sound?

Analogue sound wave is recorded using a microphone

Sound wave is sampled measuring height and amplitude

Each amplitude has a unique binary value

Sample rate is set which is the number of samples taken per second

Sample resolution is set which is the number of bits used for each sample

Each sample converted to binary

Sample rate

Number of samples taken per second

Sample resolution

Number of bits per sample like 16 bits.

Provides variation in amplitude that can be stored for each sample.

Determines how loud or quiet the sounds are which can be recorded

Why do analogue sounds and text and images have to be converted to digital

Computer can only process binary data.

How can accuracy of recording increase, and what does it cause?

Sample rate increase and resolution increase making file size increase

Image

Series of pixels that are converted to binary

Image resolution

Number of pixels in an image, number of pixels up times pixels wide, dimensions of an image

Colour depth

Number of bits used to represent each colour

How do you increase quality of an image and what does it cause

Increased resolution and colour depth causing increased file size

Pixel

One square/ one circle of a colour/ smallest component of the image

Benefits of increased colour depth of image

Image will be more detailed

Closer to the actual contents of the image in real life

It will have a greater range of colours