An ECG recorder and playback unit which includes software-implemented digital signal processing filters which compensate for phase and magnitude distortion occurring when an ECG signal is recorded on a Holter recorder and played back. This permits "tuning" a recorder and playback unit which may be unrelated,...http://www.google.de/patents/US5553623?utm_source=gb-gplus-sharePatent US5553623 - Method for calibrating a system for recording and playing back ECG signals
