Digital Information

Abstract

Information is available in an analogue form or in a digital form. These forms are shown in Figure 2.1. Computer-generated data can be easily stored in a digital format, but analogue signals, such as speech and video, require to be sampled at fixed intervals and then converted to a digital form. This process is known as digitization. The advantages of converting analogue information into digital are that:

• Digital data is less affected by noise, as illustrated in Figure 2.2;

• Extra data can be added so that errors can either be detected or corrected;

• The data does not degrade over time;

• Processing is relatively easy, either in real-time or non real-time;

• A single media type can be used to store many different types of information (such as a hard-disk or a CD-ROM);

• A digital system has a dependable response, whereas an analogue system’s accuracy depends on parameters such as component tolerance, temperature, power supply variations, and so on. Analogue systems thus produce a variable response and no two analogue systems are identical;

• Digital systems are more adaptable and can be reprogrammed with software. Analogue systems normally require a change of hardware for any functional changes.