Multi-stream data collection system for noninvasive measurement of blood constituents
The present disclosure relates to noninvasive methods, devices, and systems for measuring various blood constituents or analytes, such as glucose. In an embodiment, a light source comprises LEDs and super-luminescent LEDs. The light source emits light at at least wavelengths of about 1610 nm, about 1640 nm, and about 1665 nm. In an embodiment, the detector comprises a plurality of photodetectors arranged in a special geometry comprising one of a substantially linear substantially equal spaced geometry, a substantially linear substantially non-equal spaced geometry, and a substantially grid geometry.
1. A noninvasive physiological sensor comprising:
at least two sets of photodiodes; and
a front-end interface comprising:
one or more inputs configured to receive signals from the respective sets of photodiodes in the sensor;
respective switched capacitor circuits for each respective set of photodiodes and configured to convert the signals from the respective sets of photodiodes into output signals for each of the respective sets of photodiodes, wherein the switched capacitor circuits include at least two switched capacitor circuits, and wherein the at least two switched capacitor circuits are configured to combine the output signals of two or more of the at least two sets of photodiodes into a single stream; and
an output configured to provide the output signals, wherein the switched capacitor circuits are configured to provide analog averaging of the output signals.
2. The noninvasive physiological sensor of claim 1 , wherein the front-end interface is integrated with the sensor.