Research On Pulse Signal Conditioning Technology And Portable System Design Based On PPG

The pulse wave signal based on PPG contains a wealth of human physiological information and it is an important source of information for studying physical health.The signal can reflect important physiological information related to human health such as blood pressure,blood oxygen,cerebral oxygen,muscle oxygen,blood glucose,pulse rate,and respiratory rate in real time.Therefore,it has a good application prospect in the field of noninvasive detection of physiological information.In this paper,for the PPG-based pulse wave signal is very weak and the noise is large,the signal conditioning technology is studied and a portable pulse wave signal detection system based on PPG is developed.In this paper,we first study the theoretical knowledge of pulse wave signal extraction and conditioning circuits based on PPG by reading a large amount of literature.In the research,compared with the reflective sensor,the transmission sensor was more stable and the signal quality was better when the pulse wave signal was collected.So the pulse signal detection system using a transmission sensor was proposed.Because the original signal of pulse wave extracted from fingertip is very weak and the noise is very big,it is necessary to use the signal conditioning circuit such as amplification and filtering to process it.After a large number of experiments,the ideal pulse wave signal detection and conditioning circuit is determined and a corresponding PCB circuit board is designed and tested for experimental verification.Then based on the above experimental results,the portable system is designed and developed.The MCU with ultra-low power consumption is selected as the controller processing unit,and system circuit modules such as the sensor circuit,MCU peripheral circuit,power supply circuit,and Bluetooth chip peripheral circuit are studied and completed.After continuous trial and improvement,a portable pulse wave signal detection and conditioning system based on PPG was developed.The Bluetooth communication function between the system and the mobile phone is also designed in the article.First,the design of communication between MCU and Bluetooth chip is carried out in the lower machine part with MCU as the core,and then the design of serial communication by Bluetooth and user interface display is designed at the mobile phone end.In this way,the analysis and display of health data can be performed in the mobile terminal,and a personal health database associated with each user can be established,so that the user can grasp their own health status in real time,and can promptly seek medical treatment after the system prompts him.All of these work laid a good foundation for the further research and development of physiological parameters monitoring systems such as blood oxygenation,blood pressure,heart rate and respiratory rate using PPG-based pulse waves.At the end of this paper,functional testing and reliability testing are performed on the researched and processed system.The portable human physiological signal monitoring system has the advantages of small volume(5×3×3cm~3),easy to carry,simple external structure,low power consumption(up to 3 months of standby time),safe and stable,and rich practical functions,and can continuously monitor the health status of the user in real time.