Abstract: Embodiments of the present disclosure include an optical probe capable of communicating identification information to a patient monitor in addition to signals indicative of intensities of light after attenuation by body tissue. The identification information may indicate operating wavelengths of light sources, indicate a type of probe, such as, for example, that the probe is an adult probe, a pediatric probe, a neonatal probe, a disposable probe, a reusable probe, or the like. The information could also be utilized for security purposes, such as, for example, to ensure that the probe is configured properly for the oximeter, to indicate that the probe is from an authorized supplier, or the like.

Abstract: The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe, such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light emitting element such as a light emitting diode.

Abstract: The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe, such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light emitting element such as a light emitting diode.

Abstract: The method and apparatus of the present invention provides a system wherein light-emitting diodes (LEDs) can be tuned within a given range by selecting their operating drive current in order to obtain a precise wavelength. The present invention further provides a manner in which to calibrate and utilize an LED probe, such that the shift in wavelength for a known change in drive current is a known quantity. In general, the principle of wavelength shift for current drive changes for LEDs is utilized in order to allow better calibration and added flexibility in the use of LED sensors, particularly in applications when the precise wavelength is needed in order to obtain accurate measurements. The present invention also provides a system in which it is not necessary to know precise wavelengths of LEDs where precise wavelengths were needed in the past. Finally, the present invention provides a method and apparatus for determining the operating wavelength of a light emitting element such as a light emitting diode.

Abstract: Previously undesired artifacts in a color signal used in fiberoptic cardiac catheters to measure blood oxygenation levels are used to produce indications of blood flow and true pulse. For this purpose, the color signal is band-pass filtered to derive a DC mean signal level .mu. and an AC signal containing only those frequencies at which the signal is affected by blood flow variations. The RMS value of that band-pass-filtered AC signal (which corresponds to the standard deviation .sigma. of the AC signal) is divided by the DC value .mu. to produce a .sigma./.mu. signal representative of flood flow. By clipping the AC signal and using the resulting square wave to drive a one-shot multivibrator, an indication of the patient's true pulse can be obtained.

Abstract: Disclosed herein is a method and a digital electronic steam humidifier control for use with a humidifier system including an electrode boiler to provide a normally repetitive fill, boil, fill-on-drain cycle. The humidifier control includes circuitry for providing an analog signal proportional to the electrode current, and a comparator network which receives the analog signal and a reference voltage and scaled voltages provided by additional circuitry to establish predetermined levels of electrode current at which the control responds.