A recursive digital differentiator for ECG preprocessing

A simple recursive digital low-pass differentiator is derived from a classical lossless resonator model. It is shown that the error behaviour of the proposed differentiator is more uniformly distributed with respect to an ideal differentiator than that of a typical non-recursive digital low-pass differentiator widely used in electrocardiogram processing. The recursive digital low-pass differentiator is implemented in the form of a correlation receiver model suitable for QRS detection. Three-cycle single-lead ECG test data are used to demonstrate low-pass filtering, baseline drift suppression, and R-wave detection.