Abstract: This invention is an ultra-low frequency electromagnetic telemetry receiver which fuses multiple input receive sources to synthesize a decodable message packet from a noise corrupted telemetry message string. Each block of telemetry data to be sent to the surface receiver from a borehole tool is digitally encoded into a data packet prior to transmission. The data packet is modulated onto the ULF EM carrier wave and transmitted from the borehole to the surface and then are simultaneously detected by multiple receive sensors disbursed within the rig environment. The receive sensors include, but are not limited to, electric field and magnetic field sensors. The spacing of the surface receive elements is such that noise generators are unequally coupled to each receive element due to proximity and/or noise generator type (i.e. electric or magnetic field generators).

Abstract: A system for measuring blood oxygen saturation uses a noninvasive optical technique. A patient's arterial blood is illuminated with light at two different wavelengths and the intensity of the reflected light is correlated with an oxygen saturation reference curve to determine the oxygen saturation of the patient's blood. The optical sensor includes one or more controlled heat sources which are used to maintain the patient's tissue at a predetermined temperature. Safety circuits are also provided in order to prevent thermal burns to a patient in the event of a system failure.