| 摘要 |
A noise insensitive pulse transmittance oximeter (11) is disclosed. Two LEDs (21 and 23) are included in the pulse transmittance oximeter. The LEDs alternately emit a red light pulse and an infrared light pulse. A detector (13) detects corresponding red transmittance pulses and infrared transmittance pulses that are indicative of the amount of light transmitted through tissue having blood flowing therein. A microprocesser (29) determines the peak and valley values of the red transmittance pulses and infrared transmittance pulses over a cycle. The difference between the peak and valley values for the red transmittance pulses and infrared transmittance pulses are calculated by the microprocessor. The microprocessor generates control signals that vary the intensity of the LEDs until the differences between the peak and valley values of the red transmittance pulses and infrared transmittance pulses are substantially equal.
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