ABSTRACT
The chapter reviews the recent state of the art in noninvasive biosensor circuits and systems. It presents the highlights of their own research on long-term monitoring, in particular for the brain computer interface (BCI), which aims to provide a new communication channel to the human brain that is independent of standard pathways such as muscles and nerves. Giga-ohm input impedance field effect transistor (FET) amplifiers enable the recording of biopotentials in a range of important applications: electrocardiogram (ECG) in athlete monitoring, electroencephalogram (EEG) in long-term recordings such as the BCI, and fetal ECG detection in noncompliant subjects such as cattle. There are two forms of shock: micro- and macroshock. The obvious difference between the two is the magnitude of the current that passes in the subject's body. The most common technique used to obtain the galvanic insulation of the subject is to insulate the power supply unit of the bioamplifier.
