Patent ID: 7251516

Claim:
A noninvasive glucose sensor comprising: at least one emitter; at least one photo detector configured to detect emissions from the emitter; a controller coupled to the at least one emitter adapted to control infrared emission by the emitter including shifting of emitter wavelength to measure absorption at a plurality of wavelengths through a common optical sample volume, and deriving a glucose concentration measurement from measured absorption values wherein: the controller controls the at least one emitter to shift emitter wavelength by at least one nanometer between two measurement samples in a range from ±5 nm from a selected center wavelength, resulting in two independent equations with two unknown concentrations of analytes glucose (G) and water (W) the equations being of the form: A λ1 =ε λ1 G G+ε λ1 W W A λ2 =ε λ2 G G+ε λ2 W W where A is absorption and ε is absorption factor of an analyte at a wavelength, the controller solving the equations for glucose concentration (G) and water concentration (W) using equations of the form: G = ɛ λ2 W ⁢ A λ1 - ɛ λ1 W ⁢ A λ2 ɛ λ1 G ⁢ ɛ λ2 W - ɛ λ1 W ⁢ ɛ λ2 G W = ɛ λ1 G ⁢ A λ2 - ɛ λ2 G ⁢ A λ1 ɛ λ1 G ⁢ ɛ λ2 W - ɛ λ2 G ⁢ ɛ λ1 W .