Method and apparatus for calibration to reduce coupling between signals in a measurement system
First Claim
1. An apparatus for measuring one or more blood constituents in a subject using a plurality of light emitters configured to emit different wavelengths of light one at a time during physiological measurements, said apparatus comprising:
- a first light emitter which, during normal operation, emits light of a first wavelength during a first time interval;
a second light emitter which, during normal operation, emits light of a second wavelength during a second time interval;
a third light emitter which, during normal operation, emits light of a third wavelength during a third time interval;
a detector which detects the light emitted by the first, second and third signal sources after attenuation by tissue of a patient, said detector generating a detector output signal responsive to the detected light; and
a signal processor which receives said detector output signal, said signal processor configured to demodulate said detector output signal by applying a first demodulation signal to a signal responsive to said detector output signal to generate a first demodulator output signal corresponding to the light of the first wavelength, applying a second demodulation signal to said signal responsive to said detector output signal to generate a second demodulator output signal corresponding to the light of the second wavelength, and applying a third demodulation signal to said signal responsive to said detector output signal to generate a third demodulator output signal corresponding to the light of the third wavelength, said signal processor configured to select said first demodulation signal, said second demodulation signal and said third demodulation signal to reduce crosstalk between said first, second, and third demodulator signals using, at least in part, calibration data, wherein said calibration data comprises calibration data from a calibration procedure wherein said first light emitter, said second light emitter, and said third light emitter are operated two at a time during a second modulation operation period.
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Abstract
A method and an apparatus for separating a composite signal into a plurality of signals is described. A signal processor receives a composite signal and separates a composite signal into separate output signals. Feedback from one or more of the output signals is provided to a configuration module that configures the signal processor to improve a quality of the output signals. In one embodiment, calibration data from multiple calibration data sets is used to configure the demodulation of the composite signal into separate output signals.
1077 Citations
12 Claims
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1. An apparatus for measuring one or more blood constituents in a subject using a plurality of light emitters configured to emit different wavelengths of light one at a time during physiological measurements, said apparatus comprising:
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a first light emitter which, during normal operation, emits light of a first wavelength during a first time interval; a second light emitter which, during normal operation, emits light of a second wavelength during a second time interval; a third light emitter which, during normal operation, emits light of a third wavelength during a third time interval; a detector which detects the light emitted by the first, second and third signal sources after attenuation by tissue of a patient, said detector generating a detector output signal responsive to the detected light; and a signal processor which receives said detector output signal, said signal processor configured to demodulate said detector output signal by applying a first demodulation signal to a signal responsive to said detector output signal to generate a first demodulator output signal corresponding to the light of the first wavelength, applying a second demodulation signal to said signal responsive to said detector output signal to generate a second demodulator output signal corresponding to the light of the second wavelength, and applying a third demodulation signal to said signal responsive to said detector output signal to generate a third demodulator output signal corresponding to the light of the third wavelength, said signal processor configured to select said first demodulation signal, said second demodulation signal and said third demodulation signal to reduce crosstalk between said first, second, and third demodulator signals using, at least in part, calibration data, wherein said calibration data comprises calibration data from a calibration procedure wherein said first light emitter, said second light emitter, and said third light emitter are operated two at a time during a second modulation operation period.
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2. An apparatus for measuring one or more parameters in a subject using a plurality of light emitters configured to emit different wavelengths of light one at a time during physiological measurements, said apparatus comprising:
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three or more sources; at least one detector configured to sense electromagnetic radiation produced by said three or more sources, the detector outputting a detector signal; and a signal processor which receives said detector output signal, said signal processor configured to demodulate said detector output signal by applying a first demodulation signal to detector signal to generate a first demodulator output signal, applying a second demodulation signal to said detector signal to generate a second demodulator output signal, and applying a third demodulation signal to said detector signal to generate a third demodulator output signal, said signal processor configured to select said first demodulation signal, said second demodulation signal and said third demodulation signal to reduce crosstalk between said first, second, and third demodulator signals using calibration data, wherein said calibration data is obtained by activating said three or more sources according to a set of activation patterns, wherein the number of activation patterns is greater than the number of sources in said three or more sources. - View Dependent Claims (3, 4, 5)
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6. An apparatus for measuring one or more blood constituents in a subject using a plurality of light emitters configured to emit different wavelengths of light one at a time during physiological measurements, said apparatus comprising:
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a first signal source which applies a first input signal during a first time interval during normal physiological measurements; a second signal source which applies a second input signal during a second time interval during normal physiological measurements; a third signal source which applies a third input signal during a third time interval during normal physiological measurements; a detector which detects a first parametric signal responsive to said first input signal passing through a portion of said subject having blood therein and which detects a second parametric signal responsive to said second input signal passing through said portion of said subject, and a third parametric signal responsive to said third input signal, said detector generating a detector output signal responsive to said first, second, and third parametric signals; and a signal processor which receives said detector output signal, said signal processor demodulating said detector output signal by applying a first demodulation signal to a signal responsive to said detector output signal to generate a first demodulator output signal and applying a second demodulation signal to said signal responsive to said detector output signal to generate a second demodulator output signal, said first demodulation signal determined at least in part from a first dataset wherein each of said first, second, and third sources are activated one at a time and a second dataset wherein each of said first, second, and third sources are deactivated one at a time. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification