Analogue represents information through continuously varying physical quantities, while digital represents information using discrete values, usually binary digits. This distinction is part of IB Digital Society topic 1.1 and is shared by SL and HL.
| Analogue | Digital |
|---|---|
| Represents a continuous range of values | Represents separate, discrete values |
| Uses physical variations such as voltage, position or grooves | Uses encoded data, normally binary digits, represented as and |
| Can reproduce subtle continuous variation | Can be stored, processed and copied reliably by digital systems |
| Is directly affected by physical noise and deterioration | May use error detection and correction, although data can still be corrupted or lost |
For example, an analogue audio signal varies continuously with the original sound wave. To create digital audio, a system measures the signal at regular intervals through sampling. Each measurement is assigned one of a fixed number of values through quantization, and these values are encoded in binary.
This conversion is called digitization: changing data or information from analogue to digital form. A higher sampling rate and bit depth can represent the original signal more accurately, but the digital representation remains discrete rather than continuous. Digitization also creates trade-offs because greater accuracy generally requires more data storage and transmission capacity.
A common misconception is that analogue means “old” and digital means “new” or “online.” The actual distinction concerns how information is represented. An analogue device can be modern, and digital data can exist on an offline device. Digitalization is also different from digitization: digitalization means using digital systems to change the structure or operation of an organization.
Exam technique: For an IB question asking you to distinguish analogue from digital, refer to continuous versus discrete representation and address both terms throughout. If asked to explain digitization, include the sequence of sampling, quantization and binary encoding rather than merely stating that information “becomes digital.”
