NONINVASIVE PULSED INFRARED SPECTROPHOTOMETER

A method and apparatus for monitoring glucose, ethyl alcohol and other blood constituents in a noninvasive manner. The measurements are made by monitoring infrared absorption of the desired blood constituent in the long infrared wavelength range. The long wavelength infrared energy generated by source (400) is passed through a finger (406). To prevent the high energy source from burning or causing patient discomfort, shutter (404) and bandpass filters (410) cause only shor t bursts of energy to be sent through the finger with a very low duty cycle and low optical bandwidth. The bursts are further synchronized by shutter (404) with systole and diastole of the cardiac cycle so that only two pulses are sent per heart beat, one during diastole and one during systole. The detection signals measured at detectors (412) during application of these bursts of energy are used to calculate the concentration of blood constituents in accordance with a polynomial equation.