Patent Document ID: 5533507
Application ID: 08225486
Patent Flag: 1

Claim One:
1. A method for determining a parameter of blood, comprising the steps of: emitting a first and second wavelength of light through a sample; detecting said first and second wavelengths of light through said sample: producing first and second analog signals responsive to the detection of said first and second wavelengths, respectively, said first and second analog signals being proportional to the intensity of said first and second wavelengths of light, respectively, said first analog signal having an AC and a DC component, and said second analog signal having an AC and a DC component; separating said AC component of said first analog signal from said first analog signal to produce a first separated AC component, and separating said AC component of said second analog signal from said second analog signal to produce a second separated AC component; computing the derivatives of said first and second separated AC components; and computing said parameter of blood, said parameter of blood being dependent on the derivatives of said first and second separated AC components.