1. data representation
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what is ASCII code
standard character set used worldwide to represent characters in a computer system.it originally only represents english language
how many bits does ASCII code use?
7 bits which represents 128 different characters.
why a computer represents text and the use of character sets
Text is converted to binary to be processed by a computer
what is Unicode character set
Unicode allows for a greater range of characters and symbols than ASCII, including different languages and emojis
how many bits does unicode use?
16 bit combination
what waves is for real sound and computer sound
real sound uses analogue waves and sigital sound is made by digital waves
what are digital wabes
a sequence of discrete signals desighned to give the ilusion of constantly changng siunt- a complex series of on and off instructions
what is sampling
a sound to be converted to binary, which is processed by a computer
what is the sample rate
the number of samples taken in per second
what is the sample resolution of an image
The resolution of an image is the number of pixels in the width × the height of the image.
what does the bit depth refer to?
refers to how many bits are used to store the colours in each pixel of the image
what is the relation between the accuracy of the recording and the sample rate and resolution
The accuracy of the recording and the file size increases as the sample rate and resolution increase
what is a image
An image is a series of pixels that are converted to binary, which is processed by a computer
what is the resolution of an image
• The resolution is the number of pixels in the image
what is the colour depth of a image
the number of buts used to represent each colour
what is the relationship between file size and uality with resolution
The file size and quality of the image increases as the resolution and colour depth increase
what are the ways data can be measured
• bit ( 1 or 0) – nibble( 4 bits) – byte ( 8 bits) – kibibyte (KiB) ( 1024 bytes) all 1024 of previous measurement in bytes – mebibyte (MiB) – gibibyte (GiB) – tebibyte (TiB) – pebibyte (PiB) – exbibyte (EiB)
how to calculate the file size of an image
image file size= ( image width x image eight) x bit depth
how to calculate the size of a sound file
sound file size = sample rate × sample resolution × length of track
what is compression
compression involves applying an algorithm to a file in order to reduce the size of the file
what are advantages of compression
– less bandwidth required – less storage space required – shorter transmission time
what is lossless compression
Lossless compression reduces the file size without permanent loss of data, e.g. run length encoding (RLE)
what is lossly compression
Lossy compression reduces the file size by permanently removing data, e.g. reducing resolution or colour depth, reducing sample rate or resolution