Sigma Delta Modulation for Human Sensing

Sigma Delta Modulation (SDM) is a well known modulation principle, with several interesting applications. With SDMs, for example, very accurate Analog-to-Digital Converters and Digital-to-Analog Converters can be realized. SDMs exploit advantages of modern IC technologies like their high speed and accurate timing properties, and can deal with disadvantages, like the low allowable supply voltages of modern ICs.

Due to the strong expertise in the field, the long track of successful trainee, master and Ph.D. students and the well established industrial relations, the MsM group has a world-top position in SDM research.

A very interesting area for the application of SDMs is in sensor electronics and in human sensing in particular. In electro-physiological human sensing, like electrocardiography (ECG) and electroencephalography (EEG), most often electrodes are connected to the body, using conductive gel. This can be very inconvenient, especially when the patient has to be sensed for longer periods in daily life. As an alternative to the gel type of electrodes, contactless electrodes can be used, for which no ohmic contact to the body is needed. An important problem of contactless electrodes is the artefacts that are generated, due to the changing distance between the electrodes and the human body.

It turns out that by using sigma-delta techniques in the sensor electronics significant improvements of the sensor operation can be achieved. The initial simulations and the measurements done with a small discrete hardware setup seem promising; however further research, experiments and improvements of the experiment need to be conducted.

For this research, the MsM group is looking for a trainee, who will do this project at the university, but in close cooperation with Philips Research Eindhoven. In the case of positive results, this work might be extended to MSc thesis project.

Supervisor:           Pieter Harpe
Project duration:   9 months