Thomas Degen

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We present a wrist worn fall detector for elderly people. The detector is easy to wear and offers the full functionality of a small transportable wireless alarm system. It implements a fall detection algorithm which will alert a call center after a heavy fall. This occurs even if the wearer is unconscious or too agitated to press the alarm button himself.(More)
The use of preamplified electrodes in electrocardiography (ECG) or electroencephalography (EEG) has a numbe of benefits, most importantly, the noise reduction through preamplification and the interference reduction through buffering (Fernandez and Pallas-Areny, 1997). Normally, preamplified electrodes are not used because the mismatch in amplification due(More)
Active buffer electrodes are known to improve the immunity of bioelectric recordings against power line interferences. A survey of published work reveals that buffer electrodes are almost exclusively designed using operational amplifiers (opamps). In this paper, we discuss the advantage of utilizing a single transistor instead. This allows for a simple(More)
Most wired active electrodes reported so far have a gain of one and require at least three wires. This leads to stiff cables, large connectors and additional noise for the amplifier. The theoretical advantages of amplifying the signal on the electrodes right from the source has often been described, however, rarely implemented. This is because a difference(More)
In bioelectric recordings the electrode-skin impedance mismatch reduces the common mode rejection ratio (CMRR) of the amplifier. For this reason, the impedance of each individual electrode-skin contact is usually measured prior to a recording. The measurement circuit itself degrades the CMRR and is switched off during the bioelectric recording. In this work(More)
In bioelectric recordings, an electrode-skin impedance mismatch leads to a reduced common-mode rejection ratio (CMRR) of the amplifier. For this reason, the impedance of each individual electrode-skin contact is usually measured prior to a recording. The measurement circuit itself degrades the CMRR and is switched off during the bioelectric recording. In(More)
Today’s professional audio systems consist of expensive devices that require elaborate wiring. Changes to installations are complex and errors are hard to localize. System development requires a great amount of effort, while the market is very limited. For this reason we have envisioned an audio system that is composed of services, interfaces and(More)
Instrumentation amplifiers are widely used in biosignal measurements, due to their good common mode rejection ratio (CMRR) and their high input impedance. While the fabrication of active electrodes has been reported and their beneficial effects scientifically confirmed their usage in daily practice is still limited. This work describes a new instrumentation(More)
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