基于MATLAB的心电信号的数字滤波处理

心电信号是一种基本的人体生理信号,然而体表检测人体心电信号中常带有工频干扰、基线漂移和肌电干扰等各种噪声,为了得到不失真的原始心电信号,在显示信号前要进行必要的滤波预处理。本文在分析数字滤波器设计原理的基础上,介绍了处理心电信号中滤波器的设计。     

LMS自适应滤波对ECG双频干扰的估计与消除

在采集心电信号过程中,传感器经常受到其它用电设备带来的工频噪声干扰，以及由病人呼吸、皮肤阻抗、运放温漂等产生的0.05～2 Hz基线漂移噪声干扰，其频段范围与心电信号ST段频谱成分接近，这些对心脏疾病的判断会产生影响，如何有效地消除此类干扰显得尤为重要。通过MATLAB仿真，对带噪信号采用级联型LMS自适应滤波系统,同时滤除工频50 Hz干扰及2 Hz基线漂移。仿真结果表明，此方案不仅可以摆脱传统滤波方法的局限性，还可以有效去除双频干扰,为后期算法布署嵌入式硬件提供了新思路。     

羽毛球运动员表面肌电信号采集与提取仿真

为更精确地分析羽毛球运动员上肢运动细节,提出基于表面肌电信号的采集与提取方法。采集不同的肌电信号反映动作状态,提取上肢局部动作特征向量,利用小波变换结合自适应滤波的方法对采集的不同动作对应的表面肌电信号进行预处理,获得纯净的表面肌电信号。利用神经网络算法比较表面肌电信号时域特征、频域特征以及时频特征对羽毛球运动员上肢运动的影响。通过计算机仿真验证上肢运动模拟模型合理性,结果表明,所提方法能有效采集羽毛球运动员上肢运动的规律,识别正确率高,动作执行完整度高。     

表面肌电信号有源低通滤波器设计与验证

在运动康复治疗中,需要一种即能够滤除信号中的干扰,又能够放大信号的有源滤波器提取相关肌肉运动产生的表面肌电信号,以评估康复治疗效果。基于多重反馈型滤波器设计一种表面肌电信号的有源低通滤波器,并通过仿真进行验证。     

心电信号处理中的数字滤波器的设计

心电信号是一种基本的人体信号,其中常带有肌电干扰、基线漂移和工频干扰等各种噪声,为了得到不失真的原始心电信号,在显示信号前要进行必要的滤波预处理.介绍了处理ECG信号中滤波器的设计,包括去除噪声的低通、高通和带阻滤波器.     

多通道表面肌电信号同步采样与处理研究

在康复机器人的人机交互系统中,表面肌电信号(sEMG)发挥着重要作用。针对采集单通道的肌电信号已经不能满足获取更多信息量的需求,该文设计一个8通道的肌电信号同步采集系统。该系统包括表面电极贴片、仪表放大器、带通滤波与二级放大、50 Hz陷波器、同步采集ADC和无线蓝牙模块等部分。通过测试实验,该采集系统很好地采集了人体的表面肌电信号,有效去除了共模噪声和50 Hz的工频干扰。获取的同步肌电信号可以进一步用于人机交互系统的模式识别研究。     

心电信号检测中滤除肌电干扰的方法

心电信号检测是医生诊断治疗心血管疾病的重要辅助手段,但由于心电信号检测实际条件不理想,心电信号中常混有各种干扰信号,常见有肌电干扰、基线漂移和工频干扰。文中针对肌电干扰,采用数字滤波方法进行了去除噪声的滤波器设计。并通过对心电图信号滤波器的设计,不仅提高了ECG信号滤波器的去噪效果,且提高了工作效率。     

自适应相干模板法在心电图机中应用的一种改进算法

自适应相干模板法是一种高效的数字滤波器。但原算法在应用时仍存在一定的问题,如在滤除工频干扰和基线漂移时,难以同时兼顾两者的阻带特性。本文对此作了进一步地研究,使该算法同时滤除工频干扰和基线漂移均能得到十分满意的效果。     

脑电信号检测用的含工频陷波OTA-C低通滤波器

由于研究脑电的需要,研制检测脑电信号的专用集成电路具有重要的意义。提出了一种基于CSMC的DPDM 0.6μm CMOS工艺可集成低通椭圆滤波器的设计。该滤波器的特点是同时实现了低通滤波和工频陷波的功能,它是针对脑电信号的检测采用基于跨导运算放大器和电容(OTA-C)结构而设计的。通过Cadence公司的Spectre仿真结果看,该滤波器通带符合设计要求,对50 Hz工频干扰的衰减达到58.5 dB,实现了工频陷波功能。     

HHT在脑电信号去噪中的应用

脑电信号在采集过程中极易受到噪声的干扰,如何有效地去除混入脑电信号中的噪声已经成为信号前期处理的难点。根据脑电信号和噪声的特点,使用HHT方法去除脑电信号中的工频噪声,并通过信噪比和均方误差对去噪效果进行了检测。仿真结果表明该方法不仅能够有效地抑制工频噪声,还可以较好地保持脑电信号的波形特征。     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.