Abstract A blood glucose monitoring system is disclosed which provides for inducing an active pulse in the blood volume of a patient. The induction of an active pulse results in a cyclic, and periodic change in the flow of blood through a fleshy medium under test. By actively inducing a change of the blood volume, modulation of the volume of blood can be obtained to provide a greater signal to noise ratio. This allows for the detection of constituents in blood at concentration levels below those previously detectable in a non-invasive system. Radiation which passes through the fleshy medium is detected by a detector which generates a signal indicative of the intensity of the detected radiation. Signal processing is performed on the electrical signal to isolate those optical characteristics of the electrical signal due to the optical characteristics of the blood.
A method of actively varying the attenuation of optical radiation due to blood in a fleshy medium comprising the steps of: transmitting optical radiation through said fleshy medium; detecting said optical radiation after attenuation through a field of view through said fleshy medium; generating an output signal indicative of an intensity of an attenuated signal; and applying pressure to said fleshy medium according to a predictable cyclic pattern to influence a cyclic change in the volume of blood in said fleshy medium in said field of view to produce no more than 40% modulation in said attenuated signal.
Claim 2
Independent Claim
98 words
A method of actively varying the attenuation of optical radiation due to blood in a fleshy medium comprising the steps of: transmitting optical radiation through said fleshy medium; detecting said optical radiation after attenuation through a field of view through said fleshy medium; generating an output signal indicative of an intensity of an attenuated signal; and applying pressure to said fleshy medium according to a predictable cyclic pattern to influence a cyclic change in the volume of blood in said fleshy medium in said field of view to produce no more than 40% modulation in said attenuated signal.