心率检测系统的设计论文
心率检测系统的设计论文，ti杯电子设计大赛优秀论文右手接至低通前置放大电路滤波器输左手入端共模电压右腿驱动屏蔽动右腿退导联屏蔽线图2前置放人电路框图1)前賢放大调理针对心电信号高增益,高输入阻抗,高垬模抑訇比,低噪声,低漂移和合适带宽的采集要求,采用仪表放大器,以获得良好的综合性能。所以采用仪用放大器AD620只要用只外接电阻便可设置放大器的增益,增益G为494人R2)右腿驱动电路将右腿连接到一个辅助的运算放大器的输出端,把混杂于原始心电信号中的共模噪声提取出来,经过一级倒相放大后,再返回到人体,使它们相互叠加,从而减小人体共模干扰的绝对值,提高信噪比。本电路采用高精度运算放大器O217。通过这个负反馈结构,可大大抑制测量过程屮前置敚大器输入端共模电压的影响。此外,右腿驱动电路还可以提供电气上的安全性。3)屏蔽驱动电路屏蔽驱动器是一个同相电压跟随器,将放大器的输出端和屏蔽相连,将屏蔽线和地隔开,并且对于50Ⅳz的共模干扰信号来说,从人体输入的两路信号是相等的导联线和屏蔽线之间的电压差为0,从而消除了其间的电容,提高了输入电路的阻抗,降低人与地之间的漏电流。如图3所小220kTT1点2R图3带屏蔽驱动、右腿驱动的前置放大调理电路经过前置放大器后心电信号被放大的倍数为49.4KG=1+51IK∥(24.9K+24.9K)(2)高通滤波电路的设计电极与皮肤表面之间容易产生直流偏压,为了消除这部分的干扰,需要采取高通滤波电路图4所示予以滤除,其截止频率为≈0.5Hz2丌√RR,CC22x√22X×47K×101×10U4BQPZITT图4二阶高通滤波电路(3)低通滤波电路的设计噪声来源一类是各种电子设备辐射出的高频噪声,一类是市电的50z噪声。通常情况下后者影响尤为明显。对这些噪声的滤波需要用到滤波器。低通滤波器(电路图如图5)通常情况下截止频率选择在100Hz以下。低通截止频率为2兀√RR1CC42√24K×24K×0.047×Dm≈100H2T745TQP2171图5二阶低通滤波电路(4)50Hz陷波电路的设计为了去除人体或测试系统中产生的工频50Hz干扰34,需用带阻滤波器加以抑制。我们采用心电测量没备当前普煸采用的双T陷波电路滤除工频干扰,其参数计R算公式为:2可C其中f为滤去频率,如图6所小。USD图650Hz陷波电路(5)后置放大电路及抬升电路的设计因为wsP430F169模数转换器的范围为0~2.5V,所以要对采集的心电信号进行拾升如此在实现后置放大的过程中,既要考虑信号中平的提升,又要实现信号的放大。放大器芯片用INA217。具体电路如图7所示图7后置放大发抬升电路放大倍数为:G=110K10KRIK抬升电路有对放大信号拾升了1.25V(6)电源电路的设计电源电路的设计是由电平转换器760,线性调节器MX8511,电压基准REF3025及电池盒组成,如图8所示电源电路图8电源电路31.3元件的布局和PCB板的设计在PCB板中,包含多种类型的电路,为了避免各部分电路中信号相互耦合而生千扰,对不同类型的电路部分进行分离布局是PCB板设计的一个基本原则。各部分之间不仅应保持相当距离,还要分开走线。电源系统的布线包括电源线VDD和地线vSs的布线,是系统抗干扰的个重要部分。VDD和wSS应尽可能扩大面积,以防止因电磁能量较强而产生电磁干扰能量的发射,这也是保证高频信号到地之间具有低阻抗的措施3.2软件设计软件设计的关键是对MSP430F169的控制以及LCD显示。所有软件均采用C语言绽写。软件实现的功能是QRS波检测并算出心率,LCD显小波形以及SD卡存储3.2.1软件流程系统软件部分流程图9如下所示,开关按键按下后,屏幕显示L0GO图(江苏省TⅠ杯电子设计大赛),通过对各模块的初始化后,由中断定时服务实现对心电信号QRS波检测,心率计算,波形回放。系统初始化A/D采集LCG0显示N按键显示模块初始化
- 2020-12-01下载
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基于高光谱成像的蓝莓内部品质检测 特征波长选择方法研究
在特征波长选取方面有一些创新，可以作为参考。在特征波长选取方面有一些创新，可以作为参考。（基于高光谱成像的蓝莓内部品质检测特征波长选择方法研究古文君1 ，田有文 1* ，张芳1 ，赖兴涛 1 ，何宽1 ，姚萍1 ，刘博林 2）586-482016620010~15mm0.8~2.3g。fone3:(InSpector V10E, Spectral InFinland)1392pix×1040pixCCDL CCD2(IGV-B141OM, IMPERX Incorporated, USA), 150W1. CCD Camera; 2.Spectrometer; 3.Shot; 4. Light source; 5. Samples(3900 Illuminatior, Illumination Tech6.Translationplatform7.Lightsourcecontroller;8.computernologies inc.,USA)、(IRCP0076-19. Translation platform controllerCOM,)、(120cm×50cmx(DELL VoStro 5560D-1528Figure 1 Schematic diagram of hyperspectral imagingcmsystem400~1000nm,4722.8nmRRGY-4(10mm)(DBR45(successive projections algorithm, SPA(stepwise multiple linear regression, SMLR)(SPA)(SMLR)SPASPASMLRSPA-SPA、SMLR_SMLR、SPA- SMLRSMLR-SPA21994-2018ChinaAcadcmicJournalElcctronicPublishingHousc.Allrightsrcscrved.http://www.cnki.nct5871.6BP(error back propagation)BP17(correlation coeffiient of calibration, Re)(root mean square error of calibration set, RMSEC)correlation coeffiient of pre-diction, Rp)(root mean square error of prediction set, RMSEP)ENVI 4.8(Research System Inc, ), MATLAB 2014a(The Math Works Inc)、TheUnscrambler9.7、 Excel2010(Ⅵ icrosoftdgle banddWcvef.BP models for soluble solidsThe selected characteristic wavelengthCurve of relative reflectanceExtract the region of interescontent and firmness prediction2figure 2 Flow chart of data processing280mm,68ms,28mm·s-。99%202.2600nm600nm2b2c)21994-2018ChinaAcadcmicJournalElcctronicPublishingHousc.Allrightsrcscrved.http://www.cnki.nct5884823(2f)BPSavitzky-Golasavitzky -golayTable 1 The effect of different spectra preprocessingCalibration setPredictioSpectrum typeRMSECRMSEPOriginal spcctrum0.933/0.9230.3510.4040.9200.9100.508/0.319MSCThe spectrum after MSC processing0.940/0.9450.56lO.3120.9190.9320.516/0.282SNThe spectrum after SNV processin0.93709340.60210.24309220.9010.6320.462Savitzky-golayThe spectrum after Savitzky-Golay processing 0.955/0.9550.3240.2410.951/0.9490.400/0.2782.5SPA-SPA SMLRSMLR SPA-SMLR SMLR-SPASPA-SPASPASavitzky-GolaySPATable 2 The results of multi-stage characteristic wavelength selection methodnmCharacteristie wavelength selection methodSPA-SPA452,455,470,482,490,785,893,912,921,942,950455,470,482,785,893.912SMLR-SMLR457,508,516,534,543,51,556,568,712,720.774,778508,534,543,712,720,774SPA-SMLR452,455,470,482,490,785,893,912,921,942,950452,470,482,490,893,912SMLR-SPA457,508,516,534,543,551,556,568,712,720,774,78534,7202.6Savilzky-gola(FS)392SPA-SPASMLR-SMLRSMLR-SMLRSMLR-SPABPBP0.001500021994-2018ChinaAcadcmicJournalElcctronicPublishingHousc.Allrightsrcscrved.http://www.cnki.nct589BPBPSPA-SPARp RMseP0.9520.391°Brix,RpRMSEP0.9530.234BrixTable 3 Detection results of soluble solid content and firmness of blueberry based on different multi-stagecharacteristic wavelength selection methodsCalibration setPrediction setCharacteristic selection method Wavelength numberRMSECRMSEP3929550.9550.324/0.2410.9510.9490.400/0.278SPA-SPA0.9590.9560.3180.1530.9520.9530.391/0.234SMLR-SMLR0.9560.9340.414/0.243912109020.559/0.349SPA SMLR0.828/0.8581.3670.58582208091.440/0.719SMLR- SPA20.958/0.9360.402/0.3359320.9280.435/0,4041387nm1229nm91.5%BPRRMSEP0.904215.163lBP3Rv0.84V0.94Rv0.83,SEV0.63。400-1000nmSavitzky-GolayBPSPA-SPASPA-SPA21994-2018ChinaAcadcmicJournalElcctronicPublishingHousc.Allrightsrcscrved.http://www.cnki.nct59048[1 KADER F,ROVEL. 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- 2020-12-07下载
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