The application discloses a method for measuring
oxygen saturation degree of blood, comprising the following steps of (1)
direct current filtering and pre-
processing the measured digital signals after analog-
digital conversion; (2) wave filtering by an
aliasing-resistant filter and signals extraction; (3) quick Fourier FFT transformation and
elimination of motion interference signals; (4) calculation of
oxygen saturation degree of blood. And after the
elimination of motion interference signals and before the calculation of
oxygen saturation degree of blood, a step can be added in the method, namely, the range of
double frequency is more eliminated than that of
base frequency;
elimination of excursion by a lowpass can be also added in the method before the calculation of
oxygen saturation degree of blood. The invention also discloses an instrument for measuring the
oxygen saturation degree of blood with the method. The method and the instrument of the invention can quickly and effectively measure the
oxygen saturation degree of blood, and an extraction technique is added in the invention, helping largely reduce the space for use and amount in calculation of an EMS memory. Waveshape recognition on the
frequency domain helps filter the interference of motion state effectively and improve the accurateness of measurement by the instrument.