基于相关双采样技术的CCD信号处理

目的电荷耦合器件（charge coupled device,CCD）的输出信号中含有多种噪声,其中主要是复位噪声,所以在CCD信号采集系统中,一项关键技术就是去除或削弱噪声。方法本文详细介绍了CCD复位噪声的产生机理,设计了基于相关双采样技术（correlated double sampling,CDS）的CCD信号处理电路。结果通过实验验证上述信号处理电路可以有效抑制CCD噪声。结论相关双采样技术在一定程度上抑制了CCD复位噪声,有利于后续CCD信号的采集与传输。     

脉冲激光与电刺激治疗系统音频信号处理模块的研制

目的：设计一款基于TMS320VC5402DSP的音频信号处理模块,用于采集处理多模式脉冲激光与电刺激治疗系统的音乐信号,探讨不同频率成分的音频信号对治疗高血压的影响,实现多模式脉冲激光与电刺激治疗高血压治疗处方的多样化。方法：使用音频编解码芯片TLV320AIC23B实现对多模式脉冲激光与电刺激治疗系统的音乐信号的采集,利用高性能数字信号处理芯片TMS320VC5402对采集的信号进行相应的信号分析与处理。通过数字信号处理技术得到新的治疗处方应用于多模式脉冲激光与电刺激治疗系统,用于探讨不同频率成分的音频信号对治疗高血压的影响。结果：设计的硬件平台稳定可靠．可实时采集音频信号,可用于寻找对高血压治疗的有效频率成分。结论：该设计可实时采集音频信号,并运用各种信号处理的手段,产生不同的高血压治疗处方,为寻找有效治疗高血压的音频频率成分提供了可靠稳定的硬件平台。     

基于双相电流脉冲的磁刺激系统的设计

为了实现对磁刺激的优化设计,提高线圈刺激频率和充放电效率,介绍了一种基于双相电流脉冲的重复脉冲磁刺激系统的设计方法,采用了多电容组(大功率电容并联)结构的放电回路设计,同时采用单片机脉冲信号加以控制,较好地实现了双相重复脉冲。     

基于单片机的植入式神经刺激器的设计

目的:介绍了一种治疗神经功能失调疾病仪器的设计方案.方法:该设计以MSP430单片机为核心控制器,包括体外控制器和体内刺激器的硬件和软件设计.结果:该仪器器能够对体内刺激器进行参数的设置和控制,使其产生可调电压幅度、频率和占空比的脉冲信号.并能接收到体外控制器发出的控制信号并产生相应的脉冲信号,该脉冲信号作用于靶点神经,用持续的脉冲电刺激抑制不正常的神经放电,达到治疗效果.结论:该系统进一步的完善将有较好的应用前景.     

基于FMG信号的假手比例控制系统研究

假手控制方法的研究一直是假肢研究技术的一个热点问题。针对现有皮肤表面电信号作为控制源的假手存在的问题,本系统采用前臂上肢肌肉膨胀收缩产生的压力信号作为控制信息源,设计了基于肌肉力(FMG)信号的假手控制系统,包括信号采集调理、微控制器控制、电机驱动等部分。通过采集残臂端两路FMG信号,提取信号的时域信息并采用阈值算法实现了手部2个自由5个动作。根据FMG信号均值的大小,改变假手驱动电路中PWM的占空比,从而实现电动假手速度的比例调节。实验结果表明本控制系统能够有效控制假手执行动作,实现速度的调节。另外,利用LabVIEW搭建了FMG信号采集标定平台,实现了FMG信号的实时数据采集和标定。     

表面等离子体(SPR)检测电路设计

讨论了表面等离子体(SPR)光电检测电路的设计方案，采用电荷耦合器件(CCD)检测SPR角谱，设计了一种单片机CCD驱动电路。     

基于按摩的电刺激器的设计

目的设计一种基于中医按摩的电刺激仪器——将产生的电刺激信号通过中医的按摩手法给患者按摩。方法研究采用STC89C58RD+单片机作为控制器,采用LCD点阵液晶显示作为可视化的提示工具,采用4*4矩阵键盘作为输入控制接口,采用变压器作为电刺激信号升压器件。结果研究实现了预期目标,用户可通过LCD提示输入控制点刺激信号强度的按键,单片机处理后输出相应的脉冲波形,进而触发生成用于按摩的电刺激信号。结论对51单片机开发应用,实现了输入不同的频率信息,产生不同强度的电刺激信号,使人感觉不同程度的麻刺激,能够用于治疗和保健。     

低场磁共振锁场谱仪的射频脉冲发生器研制

基于现场可编程阵列（FPGA）和数字频率合成（DDS）芯片设计一个磁共振锁场谱仪的射频脉冲发生器。通过软硬件结合的方法研制一个灵活可变的射频脉冲信号发生器,输出脉冲脉宽可调,输出脉冲时间调制精度可控制在μs级别,载波频率可达300 MHz,输出射频脉冲频率相位可调。通过仿真和实验测试,证明基于FPGA与DDS的射频脉冲发生器,可以有效激励低场磁共振锁场样品产生锁磁共振信号。     

用脉冲相关参考输入对事件相关生物电信号进行自适应滤波:与信号平均技术相比较

许多生物电信号是由生理系统对内部脉冲(ECG信号)或外部脉冲(诱发电位)的电响应产生的。本文描述了一种用于对刺激信号时间锁定的事件相关信号的自适     

双向脉冲可实现的神经纤维选择性兴奋

背景：研究证明利用电刺激外周神经纤维可恢复一些因失去中枢神经控制的肌肉的功能。 目的：验证双电极1 mm较近距离下双向方波脉冲实现神经选择性兴奋的正确性,并基于此实现神经的选择性兴奋。 方法：成年Wistar大鼠8只,麻醉后暴露大鼠坐骨神经,将电极小心放于坐骨神经干,建立神经选择性刺激模型。实验用电极为自制Cuff双极性电极,刺激器采用的是Grass S88刺激器和AWG2005任意波形信号发生器。采取双电极双向刺激方式,两个电极之间距离为1 mm,刺激波形选用脉宽为0.2 ms的对称双向脉冲,其输出脉冲的幅度、脉宽和延时均可调。调节刺激强度,研究双电极双向刺激下神经兴奋性的规律,以此实现神经的选择性兴奋,并利用“碰撞法”原理验证利用双电极双向刺激方法实现神经选择性兴奋的可行性。 结果与结论：实验过程中神经动作电位的变化将经P511放大器放大后接入示波器显示,双电极刺激波形为脉宽为0.2 ms的对称双向脉冲。随着刺激幅度的增大,实现神经的选择性兴奋。说明用距离很近(1 mm)的双电极双向对称脉冲的方法实现了神经的选择性兴奋,并利用“碰撞法”原理证实了此种方法的有效性和可行性。     

Dual channel light pulse exposure timer

An instrument has been developed for routine measurement of pulse durations of lasers and pulsed light sources. A four digit light emitting diode (LED) count display is used with a range of selectable clock rates in five decades from 1 MHz to 100 Hz with a longest time duration corresponding to 99.99 s. The performance of the system was verified using a Schmidt trigger test circuit to drive an LED where the time of the drive pulse was compared to that indicated by the timer unit and where also silicon photodiodes of different detector areas were used to verify device measurement accuracy.A buffered output channel allows inspection by an oscilloscope to verify output pulse characteristics. This can be especially relevant to verify performance characteristics of a given laser/pulsed light system and to establish definitive assessments for eye safety based on relevant standards.     

'Post-lunch' sleepiness during prolonged, monotonous driving - effects of meal size

The 'post-lunch' dip is a bi-circadian phenomenon, largely unrelated to lunch, and worsened by a disturbed prior night's sleep. Despite anecdotal claims of adverse effects of larger lunches on afternoon driving ability, there is little actual driving data to support this belief. Although there have been various (non-driving) laboratory studies assessing meal size and micronutrient effects on psychological performance tests, findings are mixed. Moreover, most have not utilised heightened afternoon sleepiness after a shortened night's sleep, and few tested beyond 20 min. Using a real car interactive simulator having full size screen projection, we compared the effects on a 2h monotonous afternoon drive, of two very similar, palatable lunches ('light': 305 cal vs 'heavy': 922 cal [having 3× fat and 2× carbohydrate contents]), given double blind in a repeated measures counterbalanced design, to 12 young male drivers whose prior night's sleep had been restricted to 5h. Sleepiness-related lane drifting ('incidents'), subjective sleepiness and EEG (4-11 Hz power - indicative of sleepiness) were logged throughout. The heavy lunch caused significant increases to both incidents and EEG power, and a trend for greater subjective sleepiness. All three indices showed a significant worsening of sleepiness over the drive under both lunch conditions. Whilst there were no significant condition×time interactions, there was no difference between lunches for at least the first 30 min of the drive when, thereafter, the differences appeared. Ours was a realistic driving study, utilising typical lunches, following an unexceptional level of prior sleep loss, and where a heavy lunch exacerbated inherent sleepiness, to further impair monotonous driving.     

Design of double ultrasound pulse transmission and receiving circuit used in ultrasound thermometry

Hyperthermia treatments of tumours are attracting more and more attention from physical doctors and researchers. In particular, invasive microwave coagulation (IMC) therapy is a newly developed and effective method for the treatment of liver tumours. Generally successful applications of IMC are based on accurate temperature measurements of the tissues as the microwaves take effect. As a noninvasive technology, ultrasonic thermometry is based on the correlation between temperature and ultrasound speed or ultrasound decay coefficients of tissues. This paper presents the design of a double ultrasonic pulse transmission/receiving circuit used in ultrasonic thermometry. The circuit can synchronously produce the double ultrasonic pulse required by ultrasonic thermometry and can successfully receive weak ultrasonic echo signals. Some key wave-shapes used in experiments are presented. The experimental results indicate that the circuit is reliable and has good functionality.     

抑制MRI运动伪影的双脉冲预饱和技术的实现

目的 设计双预饱和脉冲序列，要求被激发块边缘锐利、无交叉激发，并且要求其宽度、位置可调。方法 在磁场强度为0．23T的全身开放式永磁磁共振成像仪上通过扫描水模进行研究，依据结果修改设计编写的脉冲序列直至达到期望的结果。结果 双预饱和RF脉冲、SincG RF函数及扰相梯度的联合使用，成功地得到了边缘锐利、饱和均匀的预饱和带，减小了弛豫时间对数据采集的约束和限制。结论 采用本文所述方法，可以有效实现预饱和扫描功能，获得边缘锐利的预饱和带。     

磁共振射频发射与接收线圈谐振电路特性仿真分析

目的:使射频线圈的工作频率接近于磁共振成像（MRI）的共振频率,即射频线圈处于谐振状态,从而提高MRI系统射频功率的转化效率、改善MRI图像质量。方法:在介绍MRI射频线圈谐振电路原理的基础上,对射频线圈串联谐振电路和并联谐振电路进行理论推导。采用电子电路设计软件MULTISIM搭建串联谐振电路和并联谐振电路,从射频脉冲作用瞬间、正弦稳态和射频脉冲撤除后3个阶段,分别对其谐振电路波形、幅频特性、相频特性、线圈两端的瞬时压降和稳态电路参数等进行仿真模拟分析。结果:电子线路仿真的结果能够直观地反映串联谐振电路和并联谐振电路的特性。通过电子线路参数的优化调整能使射频线圈处于最佳谐振状态,从而提高射频功率的转化效率和改善MRI图像质量。结论:谐振电路特性的仿真分析为射频线圈的设计提供了技术依据,提高了工作效率,节约了射频线圈谐振电路的设计制造成本。     

经颅磁刺激放电回路参数对线圈脉冲电流特性的影响

目的 本文分析了经颅磁刺激放电回路参数,包括放电回路中总电容（C）、放电电压（U）以及放电线圈的电感值（L）和电阻值（R）对线圈放电电流特性的影响,为经颅磁刺激放电回路参数的优化提供理论指导.方法 首先理论上对经颅磁刺激系统基本电路进行分析,得出放电电流与放电回路参数的关系式,然后通过仿真和实验相结合的方法,研究放电回路参数对线圈脉冲电流的影响.同时,利用傅里叶变换分析线圈脉冲放电电流的频域特性.结果 单独增大储能电容值,增大了线圈放电电流幅值,延长了脉冲电流上升沿时间和脉宽持续时间,减小了电流信号的主频.单独减小回路总电阻值,增大了脉冲电流的幅值,提高了电流信号的主频,但更容易使脉冲电流出现多次振荡.单独增大回路电感值,减小了脉冲电流幅值,延长了脉冲电流的上升沿时间和脉宽持续时间,电流信号主频先增大后减小.结论 在经颅磁刺激系统工程设计中,放电回路参数值要匹配,不同的回路参数取值直接影响线圈脉冲电流的特性.本研究对设计特定指标要求的经颅磁刺激系统具有理论参考价值.     

Having to stop driving at night because of dangerous sleepiness – awareness,physiology and behaviour

A large number of accidents are due to the driver falling asleep at the wheel, but details of this link have not been studied on a real road. The purpose of the present study was to describe the development of sleepiness indicators, leading to the drive being terminated prematurely by the onboard expert driving instructor because of imminent danger. Eighteen individuals participated during a day drive and a night drive on a motorway (both 90 min). Eight drivers terminated (N) prematurely (after 43 min) because of sleep‐related imminent danger [according to the driving instructor or their own judgement (two cases)]. The results showed very high sleepiness ratings (8.5 units on the Karolinska Sleepiness Scale) immediately before termination (<7 at a similar time interval for those 10 who completed the drive). Group N also showed significantly higher levels of sleep intrusions on the electroencephalography/electro‐oculography (EEG/EOG) than those who completed the drive (group C). The sleep intrusions were increased in group N during the first 40 min of the night drive. During the day drive, sleep intrusions were increased significantly in group N. The night drive showed significant increases of all sleepiness indicators compared to the day drive, but also reduced speed and driving to the left in the lane. It was concluded that 44% of drivers during late‐night driving became dangerously sleepy, and that this group showed higher perceived sleepiness and more sleep intrusions in the EEG/EOG.     

磁共振主动式射频开关设计方法研究

目的:为避免磁共振成像（MRI）系统射频线圈的发射和接收两种工作模式发生耦合,对于短弛豫时间信号的采集,要求射频开关的切换时间应尽可能短。方法:在分析被动式MRI射频开关电路结构的基础上,采用PIN二极管设计了主动式MRI射频开关电路,由直流驱动电路控制PIN二极管的导通和截止实现射频开关的切换,从而达到对射频开关及其状态的主动控制,以缩短射频开关的切换时间。结果:采用电子设计自动化软件对射频开关电路的隔离度、插入损耗、电压驻波比等性能指标进行仿真分析,符合设计要求;通过示波器对由直流驱动电路和射频开关电路外接负载的端口波形进行分析,射频开关的切换速度达到预期目标。结论:基于PIN二极管的射频开关能够有效地缩短射频开关时间,具有良好的隔离度、插入损耗和噪声系数等性能。     

电刺激器的双极性输出及保护电路设计

目的为设计一种能够输出较为复杂波形的电刺激仪的双极性输出和保护电路。方法以单向置数方式的DAC和运放电路结合,实现双极性输出;以比较器LM311进行电压判断生成单片机中断信号而实现过压保护,以齐纳二极管实现限压,以三极管、二极管和电阻组合实现限流。使用Muhisim仿真工具,以保护电路为例对电压判断、限流限压电路进行了仿真试验。结果仿真实验表明本设计中输出保护电路实现了限流限压功能,该仪器实现了波形可编程的带有输出保护功能的双极性电刺激功能。结论该设计可实现双极性输出电刺激信号。并具有电路安全保护功能,达到了预期的目标。