Research And Design Oxygen Saturation In Blood Measuring Based On Dynamic Spectra

The pulse oximeter is a continuous non-invasive and easily used instrument for detecting arterial oxygen saturation. Since its flaws in the principle,it needs further improvment in the measurement accuracy and stability. Therefore, the thesis proposes a principle based on the dynamic spectrum of pulse oximeter and uses C8051F020microcontroller as the core of the system to estimate pulse oximeter with high accuracy. To achieve this goal, the paper completed the following work:Firstly, Since the traditional measurement algorithm ignored the impact of scattering by the body, the thesis analyzed the measurement error caused by the conventional pulse oximeter measurement principle, we employed a high accuracy algorithm which was proposed by professor Gang Li:dynamic spectra method which can eliminate the influence of measurement conditions, individual differences and other factors. The method used differential optical path instead of the geometric optical path in the traditional algorithm. In this way, the accuracy of the algorithm had been greatly improved.Secondly, we designed the circuit of pulse oximeter measuring instrument according to its measuring principle which include sensor driving circuit, band pass filter circuit, amplifier circuit, voltage uplifting circuit, double-beam separation circuit, LCD display circuit and soThirdly, we use the C programming to develop the timing control,A/D and D/A conversion, data storage, LCD display and extraction feature point of the pulse wave. At last, we calculate the value of SPO2.Finally, through the analysis of the experimental data and comparing the differences of result between dynamic spectra algorithm and traditional algorithm, we draw a conclusion that the accuracy and stability of the dynamic spectrum algorithm is3%higher than the traditional algorithm.