CS unit 1 key terms

define ASCII and the codes - denary and hex.

a 7- bit character set with codes 0-127 in denary and 00-7F in hex

define extended ASCII and the codes - denary and hex

an 8-bit character set with codes 0-255 in denary and 00-FF in hex

define unicode and what bit codes does it use.

a character set that can represent characters from languages worldwide. it uses 16-bit or 32-bit codes.

what does sampling measure?

measuring the amplitude of a sound wave at regular intervals

define sampling rate and state the unit

the number of audio samples taken per second when converting analogue (continuous) sound to digital data. the unit is hertz (Hz).

what is color depth?

the number of bits used to represent each pixel’s color

what is the formula to find color depth?

number of colors = 2^number of bits

number of bits = color depth

define resolution

the number of pixels in an image, usually given by width times height

define lossy compression

permanent compression that removes unnecessary data, so the original file cant be perfectly reconstructed.

define lossless compression

compression where no data is permanently lost, so the original file can be perfectly reconstructed.