The Research Of Multi-point Pulse Signal Detection Method Based On Wireless Communication

The fluctuations of the pulse in human body contain rich physiological and pathologicalinformation.The potential cardiovascular disease can be diagnosed as early as possiblethrough analyzing the pulse signal extracted. It can save the valuable time for the preventionand the treatment of the cardiovascular disease.Now lots of work of the pulse detection andanalysis has been done and many good results have been made.The multi-point signaldetection of wireless communication is a new and effective detection methods,which isinvolved in the technology of PVDF piezo-electric film sensor,the technology of theinterface of USB,the technology of zigbee wireless communication and the technology ofsignal processing.It maks the process of detection more convenient and flexible and makes theresults of detection more accurate and rich.The five-point PVDF piezo-electric pulse sensor is used to detect the five-pointpulse information of the radial artery, which eliminates the measurement accidental error bya single-point sensor and the pulse information obtained is much more abundant.The PVDFpiezo-electric pulse sensor is designed to be a type of platform.Five circular PVDF films areembedded into five regularly arranged and independent slots. The signal conditioning circuitis made to deal with the pulse charge signal generated by the PVDF piezo-electric film andthe pulse voltage signal is accessed. The battery and antenna are installed in the back of thesensor to ensure the power provision and signal transmission in the process of the signalacquisition.The Zigbee wireless communication technology is used to transmit the pulse information,which reachs the effect of mobility, real-time, reliability, low power consumption, lowcost and small radiation effect. The interface of USB is used to connect to the PC,which realizes the result of convenient and high-speed transmission. The MCU model of theZigbee selected is CC2430and the MCU model of the USB interface chip is EZ-USB FX2that is operating in the mode of SLAVE FIFO.The process of the digital pulsesignal transmission from the Zigbee network node to the host is that the pulse signalscollected will be passed from the Zigbee network node to the Zigbee coordinator through the network. the MCU of the coordination CC2430controls the work of theEZ-USB FX2as an external host, which transmits the pulse data to PC through the USBinterface. The mode of SLAVE FIFO not only reduces the work complexity of the interfacechip of EZ-USB FX2,but also improve the transmission efficiency.The pulse information obtained needs digital filtering processing.In this articlethree filtering methods are used.they are the slide arithmetic mean filter of thepulse information by the microcontroller program, the threshold filtering of the wavelettransform and the simple integer coefficients filter based on the zero-pole offset.Thethree types of filter effects were compared in the end. In the next, thepulse information obtained is respectively analyzed in the time domain and frequency domain,which obtains a better treatment effect. In the aspect of time domain, the extraction of thecharacteristic points based on the modulus maxima and the extraction of the characteristicpoints based on the empirical mode decomposition are used. In the aspect offrequency domain, the extraction of the characteristic points based on the power spectrumestimation and the extraction of the characteristic points based on the spectral energy ratio areapplied.