- Binary
- Base two number system based on the values 0 and 1 only.
Ch 01- Bit
- Abbreviation for binary digit.
Ch 01- One’s complement
- Each binary digit in a number is reversed to allow both negative and positive numbers to be represented.
Ch 01- Two’s complement
- Each binary digit is reversed and 1 is added in right-most position to produce another method of representing positive and negative numbers.
Ch 01- Sign and magnitude
- Binary number system where left-most bit is used to represent the sign (0 = + and 1 = –); the remaining bits represent the binary value.
Ch 01- Hexadecimal
- A number system based on the value 16 (uses the denary digits 0 to 9 and the letters A to F).
Ch 01- Memory dump
- Contents of a computer memory output to screen or printer.
Ch 01- Binary-coded decimal (BCD)
- Number system that uses 4 bits to represent each denary digit.
Ch 01- ASCII code
- Coding system for all the characters on a keyboard and control codes.
Ch 01- Character set
- A list of characters that have been defined by computer hardware and software.
Ch 01- Unicode
- Coding system which represents all the languages of the world (first 128 characters are the same as ASCII code).
Ch 01- Bit-map image
- System that uses pixels to make up an image.
Ch 01- Pixel
- Smallest picture element that makes up an image.
Ch 01- Colour depth
- Number of bits used to represent the colours in a pixel, e.g. 8 bit colour depth can represent 2^8 = 256 colours.
Ch 01- Bit depth
- Number of bits used to represent the smallest unit in, for example, a sound or image file – the larger the bit depth, the better the quality of the sound or colour image.
Ch 01- Image resolution
- Number of pixels that make up an image, for example, an image could contain 4096 × 3192 pixels (12 738 656 pixels in total).
Ch 01- Screen resolution
- Number of horizontal and vertical pixels that make up a screen display.
Ch 01- Resolution
- Number of pixels per column and per row on a monitor or television screen.
Ch 01- Pixel density
- Number of pixels per square centimetre.
Ch 01- Vector graphics
- Images that use 2D points to describe lines and curves and their properties that are grouped to form geometric shapes.
Ch 01- Sampling resolution
- Number of bits used to represent sound amplitude (also known as bit depth).
Ch 01- Sampling rate
- Number of sound samples taken per second.
Ch 01- Frame rate
- Number of video frames that make up a video per second.
Ch 01- Lossless file compression
- File compression method where the original file can be restored following decompression.
Ch 01- Lossy file compression
- File compression method where parts of the original file cannot be recovered during decompression, so some of the original detail is lost.
Ch 01- JPEG
- Joint Photographic Expert Group – a form of lossy file compression based on the inability of the eye to spot certain colour changes and hues.
Ch 01- MP3/MP4 files
- File compression method used for music and multimedia files.
Ch 01- Audio compression
- Method used to reduce the size of a sound file using perceptual music shaping.
Ch 01- Perceptual music shaping
- Method where sounds outside the normal range of hearing of humans, for example, are eliminated from the music file during compression.
Ch 01- Bit rate
- Number of bits per second that can be transmitted over a network. It is a measure of the data transfer rate over a digital telecoms network.
Ch 01- Run length encoding (RLE)
- A lossless file compression technique used to reduce text and photo files in particular.
Ch 01
