An analogue-digital converter converts an analogue input signal (a DC voltage) into a digital output signal, i.e. into a proportional number.
The quantisation error caused by the stepwise digitisation in the A/D converter can be minimised by a higher resolution: A binary system with 4 bits (24) produces 15 steps and therefore a deviation of 6.6 %, an 8-bit system with its 255 steps only as a 0.5 % deviation (Figure A 16).
A/D converters have become very important due to the adoption of microelectronics in control technology, as here the signal processing is digital, however the majority of measured signals are available in analogue form.