Definitions (Information and Communication Technology)

INFORMATION AND COMMUNICATION TECHNOLOGY

Analogue signal: A signal whose value changes continuously (smoothly) with time, usually represented as a wave, such as the sound signal carried on a traditional telephone line.

Digital signal: A signal that jumps between just two levels, written as 0 (low) and 1 (high), instead of changing smoothly.

Bit: Short for binary digit; a single 0 or 1, the tiniest piece of data a computer can hold.

Byte: Eight bits taken together; computers handle and count their data in bytes.

Data storage units: Computer memory is measured in multiples of bytes, where 1024 bytes = 1 kilobyte (KB), 1024 KB = 1 megabyte (MB), 1024 MB = 1 gigabyte (GB), and 1024 GB = 1 terabyte (TB).

Analogue-to-Digital Converter (ADC): A device that converts an analogue signal into its equivalent digital signal.

Digital-to-Analogue Converter (DAC): A device that converts a digital signal back into an analogue signal.

Source: The origin of a signal in a communication system, such as sound waves or light.

Input transducer: The part at the start of a communication system that changes the original signal (sound, light etc.) into an electrical signal; a microphone is an example.

Encoder: The stage that squeezes data into as few bits as possible, so that the limited bandwidth of the channel is not wasted.

Modulator: A device that superimposes a data signal onto a carrier wave so that it can be transmitted through a channel.

Channel: The medium, such as a wire, optical fibre, or air, through which a signal travels from the transmitter to the receiver.

Demodulator: A device at the receiver that extracts the original data signal from the received carrier wave.

Decoder: The stage at the receiving end that turns the demodulated signal back into digital data and corrects errors picked up on the way.

Output transducer: The part at the end of a communication system that turns the electrical signal back into something we can see or hear; a loudspeaker is an example.

Bandwidth: The range of frequencies available on a channel for transmitting a signal.

Baseband transmission: Sending digital signals over a channel just as they are, without first changing them into analogue form; suited to short distances, such as two computers linked by a cable.

Broadband transmission: Sending data by first changing the digital signals into analogue (modulated) form, which lets them travel long distances at high speed over many frequencies; high-speed internet is an example.

Digital citizenship: The responsible and active participation of a person in the global online community, exercising the same rights and etiquette expected of a citizen in the real world.

Netizen: Short for network citizen; anyone who regularly takes part in life on the internet.

Online reputation: The impression created by a person's or organization's activity, posts, and interactions on the internet.

Digital wellbeing: Keeping your body, mind and relationships healthy by controlling how much time you give to screens compared with offline life.

Cybercrime: Any criminal activity, such as hacking, fraud, or harassment, carried out using digital devices and the internet.

Digital library: An online collection of digitized books, textbooks, and reference materials that can be accessed through the internet.

Digital payment: The electronic transfer of money, for example by scanning a QR code, without the need to handle physical cash.

Digital media: Electronic tools and platforms, such as digital TV, social networks, and online news, used for creating, sharing, and accessing information.