Chapter 1 Information Representation

denary numbers

Numbers used in everyday life, based on the base-10 system.

bit

A single binary digit (0 or 1).

byte

A group of eight bits.

nibble

A group of four bits.

decimal prefix

A prefix defining magnitude using factors based on powers of 10.

binary prefix

Names (like kibi, mebi) defining magnitude factors based on powers of 2.

one's compliment

Binary number obtained by switching every 0 to a 1 and every 1 to a 0.

two's compliment

The binary number obtained if 1 is added to the one's complement number.

overflow

An error when the result of an operation is too large for the available bits.

binary coded decimal (BCD)

A scheme using four bits (a nibble) to represent a single denary digit.

packed BCD

Storing two 4-bit BCD codes within one byte.

vector graphics

An image where components are individual scalable drawing objects.

drawing objects

An individual component defined within a drawing package image.

drawing lists

A list in a vector graphic file containing a command for each object.

property

An attribute defining a characteristic (e.g., colour, size, thickness) of an object.

picture element (pixel)

The smallest identifiable component of a bitmap image.

colour depth

The number of bits per pixel used to represent a pixel's colour.

bit depth

The number of bits used to store each primary color (Red, Green, Blue) in the RGB scheme.

image resolution

The product of the number of pixels per row times the number of rows in a bitmap file.

screen resolution

The resolution applicable to a particular monitor screen used to display an image.

file header

Part of a bitmap file containing construction information (e.g., colour depth and resolution).

analouge data

A continuous sound signal.

digital data

The binary code that sound is converted into for storage or transmission.

sampling

The process during ADC conversion where measured sound values are captured.

sampling resolution

The number of bits used to store the amplitude values (affects accuracy).

sampling rate

An important factor associated with the use of an analogue-to-digital converter (ADC).

lossless compression

File size reduction where no information is lost; the original file is recoverable.

lossy compression

File size reduction involving some loss of information; the exact original file cannot be recovered.