Fundamentals Of Data Representation Flashcards
What are number bases?
Number bases are the number of unique digits available in a numbering system such as the decimal system having 10.
Binary to Hex
Binary split into nibbles (4 bits) which are individually converted into hex and then concatenated
What is a character set?
A list of all characters recognised by a computer system. Each character has a code and the same code is used by all computers with the same character set. ASCII and Unicode
Difference between ASCII and Unicode
ASCII uses 7 bits meaning 128 characters can be represented. Unicode uses 16 bits and so 65,536 characters giving access to more alphabets from more languages.
How do you calculate image size?
Bits = Width ** Height ** Colour Depth
What is colour depth?
A measure of how many colours are available; the more colours are stored by more pixels
How is sound represented?
Sound is an analogue signal and so needs to converted to digital form. This is done by taking regular samples of the sound’s amplitudes storing the data with bits. Thousands of samples are taken per second.
What is sampling rate?
A measure of how often a sample is take, measured in Hz. 1 Hz means once per second. A higher sampling frequency means better quality of sound.
What is sample resolution?
Sample resolution is a measure of how many bits are required to store each sample.
How do you calculate the size of a sound file?
Bits = Sample Rate ** Sample Resolution ** Seconds
What is data compression? What are the 2 most common types?
Compression is a technique to reduce the size of a file so that it takes up less storage space and can be transmitted across a network more quickly.
Lossless//Lossy
What is Run Length Encoding?
A form of compression that is effective when dealing with repeating data. The data is stored once along with how many times it repeats
What is Huffman Encoding?
Huffman encoding is a form of compression that represents commonly-use characters with smaller bit patterns.
