Device and method for measuring square wave modulated photoelectric volume pulse wave

Abstract

The invention discloses a device and a method for measuring square wave modulated photoelectric volume pulse wave. A microprocessor outputs square waves which have different frequencies and form a double ratio relationship; the square waves drive at least two light-emitting diodes; the light from the light-emitting diodes are received by a photosensitive device after passing through tested finger; the photosensitive device converts the light into a voltage signal; the voltage signal is converted into a predefined amplitude value voltage signal by a current/voltage conversion amplifier; an analogue-to-digital converter converts the predefined amplitude value voltage signal into a digital signal; the microprocessor processes the digital signal to obtain photoelectric volume pulse wave and valley value and peak value thereof, and gets spectrum value by the valley value and the peak value. The measurement method comprises the following steps of: separating the digital signal to obtain the photoelectric volume pulse wave and removing interference of background light by the microprocessor; getting the valley value and the peak value according to the photoelectric volume pulse wave; and calculating the valley value and the peak value to obtain light absorbance difference, and obtaining the spectrum value by the light absorbance difference. The accurate measurement, simple circuit and low cost are realized.

Description

technical field [0001] The invention relates to a square wave modulation photoelectric pulse volume wave measuring device and a measuring method. Background technique [0002] Photoplethysmography (Photo Plethysmo Graphy, hereinafter referred to as PPG) is an important physiological signal, widely used in the analysis of cardiovascular system and blood components. For example, the measurement of blood oxygen saturation is achieved by using two or more LEDs (light-emitting diodes) to measure PPG. In these measurements, the time-division method is usually used to collect PPG and eliminate the interference of background light. [0003] The inventor finds in the process of realizing the present invention that there are at least the following disadvantages and deficiencies in the prior art: [0004] The existing multi-wavelength PPG measurement methods have disadvantages such as complex circuit structure, high requirements for devices and processes, difficult debugging, low rel...

AI Technical Summary

Problems solved by technology

[0004] Existing multi-wavelength PPG measurement methods have disadvantages such as complex circuit structure, high requirements for devices and processes, difficult debugging, low reliability, large amount of calculation, and inaccurate results.

Images