topic 2b- data representation and compression Flashcards
(15 cards)
what is a character set
a defined list of characters recognised by the computer
what is ASCII
a well known 7 bit character set with 2^7 characters (128)
what is extended ASCII
an 8-but character sec with 2^8 characters (256)
how can images be stored
bitmap or vectors
what are bitmap pictures constructed of
coloured squares called pixels
what do vectors store
the mathematics to draw coloured shapes
how is each pixel of a bitmap stored
in binary
how can the number of colours be calculated
as 2^n. where n is the number of bits for each pixel
what is colour depth
the number of bits for each pixel
meta data is additional data stored with the image to define…
the width, hight, colour depth and colour pallet
what is sound file size
the total number of bits in a sound
how do you calculate sound file size?
number of samples per second * number of bits per sample * length of sample in seconds
(spsbpsl)
what is a sample interval
amount of time that passes between capturing each sample
what is sample rate
the number of samples stored per second
what is the order of the units that measure binary value (kibbibytes etc)
bit
nibble
byte
kibibyte
mebibyte
gibibyte
tetrabyte
petabyte
