Development Of An ARM7 Based Respiration Board Using The Impedance Technology

Respiration is an important physiological parameter in clinical monitoring. Because of the advantage such as simplicity, safety, low cost, and potential for continuous monitoring, RESP monitoring using the impedance technology is now widely applied in clinical application. However most of the on-sale RESP monitoring devices have the disadvantage of being affected by the airflow, shake and the RF electromagnetic noise, and the monitoring result is unreliable. To resolve these problems, the following aspect has been explored: the low-voltage signal amplifying circuit design and filter circuit design; the ARM7 based embedded board design; board level and system level EMC (electromagnetic compatibility) design.Based on those researches, a new respiration monitoring board using the impedance technology is finished. Using the modulation method to achieve the low-voltage respiration signal; using a 24-bitΣ-ΔADC to sample the respiration wave made the circuit configuration simple; researching the board level and system EMC design to make the board unaffected by the RF noise. Signal acquisition and process is completed by the ARM7 core based embedded system, and then the respiration wave is sent to the host to display.The main performance of the new respiration monitoring system is proved to be better than the foreign products in the laboratory experiments, and performed stably in the clinical respiration monitoring. The system can be used to monitor the newborns, apnea in sleep and monitoring in the surgery. Advantages like simple structure, ability of stable work make it suitable for commercial use.