基于光-频率转换器的高精度数字脉搏血氧仪的设计

Design of Digital Pulse Oximeter with High Resolution Based on Optical-Frequency Converter

针对目前脉搏血氧仪进口成本高、功耗大、抗干扰差、检测范围小等问题,本文给出了一种低成本低功耗的数字脉搏血氧仪设计方法.采用基于光-频率转换器的高分辨数字探头提高精度和检测范围,移植直流跟踪滤波器去基线漂移提高抗干扰能力,利用上升沿和下降沿检测脉率算法提高检测准确率.本设计在人体小幅运动及手指轻度抖动时,仍能得到稳定的脉搏波形和脉率,通过使用Fluke Index2型血氧模拟仪在不同条件下进行重复实验,发现血氧饱和度为35%～100%时精度为1%、弱灌注量小于等于0.2%时精度达到4%;脉率检测的误差小于1.表明此设计在高精度、大范围、重复性和抗抖动方面均有所改善,适合于家庭、社区等医用监护场合使用.

Due to pulse oximeters have some disadvantages such as high cost of import, high power consumption, poor interference immunization,, and small detection range. In this study, we presented a kind of digital pulse oximeter with low cost and power consumption. A digital detector based on light-frequency converter and with high resolution was adopted to improve precision and detection range, A DC tracking filter was used to cancel baseline drift to improve anti-interference ability, and a pulse rate detection algorithm using rising and falling edge was utilized to improve detection accuracy. In this study, stable pulse waveforrn and pulse rate could still be captured when body moved gently and fingers trembled slightly. After repeating the experiment under different conditions by Fluck Index2 oximeter simulator, we found that the accuracy was 1% when oxygen saturation was 35% to 100 % , the accuracy was 4% when low perfusion was smaller than or equal to 0.2% ; and the pulse rate error is less than 1. In this study, the design had been improved in aspects of high precision, large scale, repetitiveness and anti-jitter. It is suitable for families, communities and other medical care occasions.