High speed and high precision electrocardiographic and plethysmographic measurement front-end

The measurements of electrocardiographic and plethysmographic signals are two of the standard measurement techniques which are performed as noninvasive spot check methods of human health condition in hospitals, home-care or other health care facilities. Therefore, specialised electronic systems exist, which perform either of the two measurements. For the separate analysis of one signal at a time this is a sufficient approach, but if the correlation of the two signals is of particular interest it might be better to combine the measurement systems into one system as a signal delay between the different measurements is avoided. This paper aims to describe a specialised hardware frontend, which is capable of high speed, high precision, concurrent and time synchronised recording of the electrocardiographic and plethysmographic signals. It makes it possible to correlate both signals and to generate new data such as the pulse transit time. This parameter is presumed to be a marker of blood pressure or stress and is therefore of high interest of being investigated.