Patent ID: 6094592
Filing Date: 2000-07-25
Classification: A61B

Abstract:
A method for use in a system for determining a physiological parameter, the system having a sensor for transmitting electromagnetic energy of first and second wavelengths toward a tissue sample and detecting the electromagnetic energy after scattering of the electromagnetic energy by the tissue sample, thereby generating a first signal corresponding to the first wavelength and a second signal corresponding to the second wavelength, the method comprising:transforming the first and second signals into a frequency domain, thereby generating third and fourth signals;generating a ratio signal using the third and fourth signals;applying more than two variable weights to various parts of the ratio signal, the variable weights being derived with reference to at least one of the third and fourth signals;for each of a plurality of ratio values in the ratio signal, generating an associated weighted sum corresponding to each time the ratio signal coincides with the ratio value associated with the sum; andselecting a best ratio value from the plurality of ratio values based on the sums associated therewith.