Abstract: Disclosed are systems and methods for using one or more light sources and associated photodetectors to determine different physiological parameters of a subject based on the subject's activity state. A processor may, for example, be configured to determine, based at least in part on data received from an accelerometer at a first time, that a first physiological parameter of the subject is to be determined, to cause the light source(s) to operate in a first manner and process signals from the photodetector(s) to determine the first physiological parameter, to determine, based at least in part on data received from the accelerometer at a second time, that a second physiological parameter of the subject is to be determined, and to cause the light source(s) to operate in a second manner and process signals from the photodetector(s) to determine the second physiological parameter.

Abstract: A matrix switch system is described with which a large number of communication lines can be interconnected. The lines are arranged in multiplex groups which are in turn sampled by multiplexers. The multiplexers in turn are coupled to matrix lines which intersect at connectable crosspoints. A common timing signal with a predetermined minimum number of time slices is used to reconfigure the system during each time slice and form the desired line connections through the multiplexers and crosspoints for signal transfer. A technique is described to allocate time slices for the various connections of the lines and minimize matrix lock conditions.