Digitizing Signals – a Short Tutorial Guide

Converting the analogue signal, as captured from a patient, into digital format is known as digitizing, or analogue to digital conversion. This is a vital first step in for digital signal processing. The acquisition of high-quality data requires appropriate choices of system and parameters (sampling rate, anti-alias filter, amplification, number of ‘bits’). Thus tutorial aims to provide a practical guide to making these choices, and explains the underlying principles (rather than the mathematical theory and proofs) and potential pitfalls. Illustrative examples from different physiological signals are provided. Figure 1. An ECG signal (analogue signal in the top plot), and the sampled version (digital signal, bottom plot). This signal was sampled at a sampling rate of 100 Hz.