Analogue Data
Data that is represented in a physical way - eg: grooves in a record
Digital Data
Pattern of binary numbers that can be interpreted by various technologies - shown as 1 and 0
Analogue Devices
- interpret analogue data is a set way (record player)
- Digital devices are generally able to interpret a wide variety of digital data, edit it and transform it
Digital Devices
- less precise and have a lower quality than analogue data
- take up less physical space
- subject to deterioration
- uses a continuous range of values to represent information where digital data uses discontinuous values
Analogue Values
To use them with a digital data device the data must be converted using a converter - ADC or DAC
Converting Analogue to Digital
First the data is sampled, the a numeric value is assigned and then sorted as binary
Sound
- Digital Representation is achieved by sampling (signal processing)
- sample quality can be affected by the sample fair and sample frequency
- the higher the sample rate + frequency, the larger the resultant sample
- the size of the storage requirement will depend on the sample rate, resolution and sound length
Light
Easter graphics are dot matrix data structures representing a gird of pixels and cannot scale up without loss of apparent quality - tend to be large in terms of memory required to store them
Bitmap Images
Type of raster image and are composed of many tiny parts called pixels, which are often many different colours - high quality = high number of pixels
Flash Drive
A memory stick that has a 2FP-2 capacity and is very durable but is expensive
External Hard Drive
A hard disk that isn’t very durable but is speedy and cheap
Magnetic Tape
Very durable and cheap but slow - disk/tape
CD/DVD/Blu-ray
A DVD that comes in a range of capacities and is very cheap but it is slow
Pixels
Small individual dots that are displayed on a computer. An image is made up of multiple pixels. The quality of the image depends on number of pixels per inch
Resolution
Number of pixels per unit of measurement, the image quality and an image that has a high resolution allows clear and sharp, realistic images to be stored and viewed
High resolution images = large file size = more time to download
Vector Graphs
Geometric primitive such as points, lines, curves, shapes or polygons based on mathematical expressions to represent images. Vector graphs can be scaled without loss of quality
Moving Images
- can be streamed from websites and this allows files to be processed and viewed before the file has been downloaded
- streaming allows video to download in background while something is playing
- buffer is temporary storage area used to hold downloaded sections of video
Data Represented
In 1 or 0
Bit
1 or 0
Nybble
4 bits (1/2 bytes)
Byte
8 bits
Kilobyte
1024 bytes
Megabyte
1024 KB
Gigabyte
1024 MB
