串并转换思想与绝对式时栅传感器的频响特性研究

在分析绝对式时栅位移传感器频响特性的基础上，介绍了一种在数字信号处理电路中的数据串并转换思想，并提出了一种基于串并转换思想的绝对式时栅信号处理电路设计方案。信号处理电路采用了复杂可编程逻辑器件（CPLD）芯片，预处理电路将测头信号进行模数转换后，经可编程多路切换器模块处理，自适应地将原始测头信号分别转换为对应的多路并行信号，各路对应的分频信号通过比相电路及传感器信号处理电路模块运算后转换为绝对位移脉冲测量信号，最后将多路绝对位移脉冲测量信号进行并串转换操作输出测量值。对信号处理电路进行了仿真，结果证明，该方法可大大提高时栅位移传感器的频响特性，从而为绝对式时栅位移传感器提供了一种应用于动态测控系统的解决方法。     

基于CPLD的光栅信号处理专用接口芯片设计

针对光栅位移传感器输出的莫尔条纹信号,采用可编程逻辑器件(CPLD)EPM7128设计研制了由4细分与辨向模块、24位可逆计数模块以及总线接口模块构成的光栅信号处理专用接口芯片。简要介绍了光栅位移传感器的工作原理,详细介绍了细分与辩向、计数和接口模块的内部算法实现逻辑及编程方法。芯片的电路设计采用硬件描述语言VHDL,开发环境应用MAXPLUSⅡ。完成的光栅位移传感器信号处理电路精度高、测量范围大,可实现数字量输出,方便的与计算机接口。     

基于数字锁相放大的时栅传感器信号处理研究

针对时栅位移传感器对信号噪声和插补时钟频率稳定性敏感及需要时钟频率高的问题,提出了一种基于数字锁相放大技术的时栅位移传感器信号处理方法。该方法用STM32F4微处理器同步产生激励信号和采集时栅输出信号,不需采集正交参考信号,将正交参考信号和输出信号送入正交矢量型数字锁相放大器,实现角位移检测。研究了基于数字锁相放大技术的时栅传感器信号处理原理和算法,设计了A/D采集电路和窄带低通数字滤波器。仿真和试验表明:在信号噪声较大条件下,时栅位移传感器的误差控制在±1.1″以内,显著提高了精度。该方法只需采集一路感应信号即可实现传感器角位移检测,优化和简化了电路结构。     

CPLD在弹丸激波信号采集电路中的应用

本文首先就弹丸激波的产生原理作了简单说明,通过传感器电路对弹丸激波信号进行采集,运用CPLD技术,就如何对后续信号进行处理、激波宽度的测量以及数据传输进行了研究,设计出了合理的后续信号处理电路和CPLD逻辑,得出精确的弹丸激波宽度.     

基于CPLD和长度计的数字化微小位移检测的设计

设计一种基于CPLD和长度计的数字化微小位移检测的系统模块.增量型长度计作为测量微小位移传感器,采用CPLD芯片作为实时信号处理芯片,通过在CPLD里编写的算法软件把增量的脉冲信号转换成为位移量,可通过总线方式将计算得到的位移量传给控制芯片.算法中包含对干扰信号的判断和滤除及微小位移变化量的计算方法.     

球栅尺读数头电路系统研究

球栅尺是一种基于交流电磁感应技术,用于极端恶劣环境下测量动态直线位移的非接触式传感器,球栅尺的读数头是传感器用于信号采集与信号处理的关键部件。针对球栅尺读数头对电路的要求,从实际应用出发,讨论了球栅尺的工作原理及基本结构,并设计了读数头的电路系统。实验表明：该球栅尺读数头电路系统能实现球栅尺信号的采集与信号处理,满足球栅尺测量系统的测量要求。     

增量式时栅位移传感器原理及试验研究

介绍了一种新型的增量式时栅位移传感器原理。通过设计传感器信号处理电路实现了其从原理到试验的转变,并且在增量式时栅位移传感器原理试验台上进行了测量试验。在分析测量数据的基础上验证了增量式时栅位移传感器原理的可行性。     

基于AT89C52单片机的容栅传感器测距系统

根据容栅传感器的检测原理,应用单片机对其输出的串行信号进行处理。设计了一套以AT89C52单片机为核心的容栅传感器测距系统,该系统通过将容栅传感器输出的串行信号转换成并行信号的方法,方便地实现单片机对容栅传感器输出信号的处理。该硬件结构简单,工作可靠,有良好的测量精度和灵敏度。文中阐述了容栅传感器的输出信号与该测距系统的硬件电路构成、工作原理及软件设计方法,并提出了一些改善系统的建议和方法。     

光纤电压传感器信号处理电路的设计

介绍了光纤电压传感器的工作原理,研究了光纤电压传感器的信号接收与处理电路部分,设计并测试了放大滤波电路、模数转换及单片机的信号处理电路,对高压测量中的误差来源进行了分析。     

基于VCSEL半导体激光器的浊度传感器设计北大核心CSCD

为更准确测量水体的水质浊度,设计一种基于半导体激光器的浊度传感器,该传感器由光学采集模块、信号处理模块、信号输出模块和电源供电模块组成。光学采集模块采用850 nm的VESEL半导体激光器为光源,采用后向散射光检测法,该方式具有宽线性范围,适用于悬浮颗粒物浊度测量。信号处理模块采用I/V转换电路、滤波检波电路、三级运放电路、振荡电路、温度补偿电路和差分放大器对采集的散射光信号进行处理。信号输出模块采用放大电路和4~20 mA转换电路将散射光信号转换成4~20 mA信号。传感器性能测试结果表明:浊度传感器准确度误差在±1.36%以内,稳定性优于0.6%,具有较高的准确性和可靠性。     

一种基于AD9850的超声波信号发生器

为满足海底沉积物声学特性的实验室测量,该文基于DDS专用芯片AD9850,设计了一种高精度可编程的超声波信号发生器。介绍了AD9850的基本原理和工作特点,给出了单片机与AD9850的硬件接口模块、功率放大电路模块。运用此信号发生器产生的超声波对海底沉积物柱状样品的声特性进行实验测量,并对实验结果进行分析。     

基于数字锁相环的FPGA多通道频率测量系统设计

针对传统频率测量电路复杂、采集速度较慢的问题,基于FPGA(现场可编程逻辑门阵列),采用全数字锁相环对待测量信号进行倍频,辅以自适应时钟模块、计数模块和串口接收发送模块,设计了多通道频率测量系统,从而达到精简电路并实现对多路待测信号的快速精准测量。实验结果表明,对于100 Hz~10 MHz频率的稳定信号,测量时间仅为100 ms,与标准频率计相比,相对误差<0.5 ppm(1 ppm=10-6)。可用于多路频率信号的实时采集测量。     

基于HCPL-7860的隔离型信号采集与传输模块的设计

为了可靠便捷地采集常用的工业信号,提出了以AD芯片HCPL-7860和微处理器PIC16F74为核心的隔离型多通道信号采集与传输模块。对HCPL-7860的特性及应用、四线制铂电阻PT100的测温原理、恒流源电路和交流信号的采集方法进行了分析和研究,给出了模块的硬件电路设计和软件设计。现场应用结果表明,该采集模块精度高,性能好,能准确可靠地采集工业常用的铂电阻测温信号,0～5V电压信号,4～20mA直流电流信号和-5A～+5A交流电流信号。     

Enhanced detection of rolling element bearing fault based on stochastic resonance

Early bearing faults can generate a series of weak impacts. All the influence factors in measurement may degrade the vibration signal. Currently, bearing fault enhanced detection method based on stochastic resonance(SR) is implemented by expensive computation and demands high sampling rate, which requires high quality software and hardware for fault diagnosis. In order to extract bearing characteristic frequencies component, SR normalized scale transform procedures are presented and a circuit module is designed based on parameter-tuning bistable SR. In the simulation test, discrete and analog sinusoidal signals under heavy noise are enhanced by SR normalized scale transform and circuit module respectively. Two bearing fault enhanced detection strategies are proposed. One is realized by pure computation with normalized scale transform for sampled vibration signal, and the other is carried out by designed SR hardware with circuit module for analog vibration signal directly. The first strategy is flexible for discrete signal processing, and the second strategy demands much lower sampling frequency and less computational cost. The application results of the two strategies on bearing inner race fault detection of a test rig show that the local signal to noise ratio of the characteristic components obtained by the proposed methods are enhanced by about 50% compared with the band pass envelope analysis for the bearing with weaker fault. In addition, helicopter transmission bearing fault detection validates the effectiveness of the enhanced detection strategy with hardware. The combination of SR normalized scale transform and circuit module can meet the need of different application fields or conditions, thus providing a practical scheme for enhanced detection of bearing fault.     

Amplification Channel for Avalanche Photodiode Signals Purposed for Spectrometric Measurements under High Peak Rates

A method of amplification and shaping of analog signals produced by a large-capacitance signal source is proposed. This method is optimized for reaching the highest signal/noise ratio, and, along with that, it allows for recognizing signals that arrive with a small time interval. An amplifying channel is designed that implements the proposed method. This channel is purposed for amplification of avalanche photodiode signals in detectors based of fast scintillators. The structure of the amplifying channel, the principle of recovering the shape of the input signal, and the basic circuit design solutions used in the developed amplifier are described.     

一种信号合成电路的设计与实现

主要设计一种能够合成指定波形的信号波形发生电路,电路基于傅里叶合成,通过产生不同频率的正弦信号,将这些信号处理后送入加法电路可合成所需信号。主要由方波产生模块产生方波,分频与滤波模块对所得方波分频并滤成正弦波,放大模块对所得正弦波幅值进行调节,移相模块调整各频率正弦波相位,最终通过信号合成模块合成所需波形。     

毛细管电泳电容耦合非接触电导检测器

设计了一种集激励、检测和数据采集功能于一体的毛细管电泳非接触电导检测器,采用文氏电桥振荡器产生激励信号,运用绝对值检波技术对检测信号进行处理,并设计USB数据采集电路和上位机软件,实现波形数据的采集、存储和图谱的绘制.介绍了其检测原理、电路结构及实现,使用葡萄糖(0.04 mol/L)+果糖(0.04 mol/L)+蔗糖(0.04 mol/L)样品进行了检测器重复性实验,并分离检测了6种酚酸,对检测器检测限作出评定.实验结果表明:峰保留时间和峰面积相对标准差分别小于1％和7.5％,对酚酸的最低检测限为5μg/mL(信噪比S/N =3),检测器灵敏度高、重复性好.     

Signal separation technology for diphase opposition giant magnetostrictive self-sensing actuator

The structure and principle of a new type of a diphase opposition giant magnetostrictive self-sensing actuator is introduced. A bridge analysis model based on variable inductance is established. Dynamic balance separation technology for the giant magnetostrictive self-sensing actuator comes true by the least means square (LMS) self-adapting algorithm. The scheme design of one important part of the circuit with the real-time separation circuit of the dynamic balance signal based on a digital signal processor is obtained. The part of the signal separated circuit is designed, which includes logarithmic-antilog practical multiplication circuit, amplifying circuit, filter circuits, and amplifier circuit. Based on the embedded system simulation software—PROTUES, the simulation effect of the circuit that separates the sensing signal from the mixed signals is obvious, which indicates that the circuit can rapidly and stably work. Moreover, the structure is simple, reliable, and meets the practical requirement.     

Signal separation technology for diphase opposition giant magnetostrictive self-sensing actuator

The structure and principle of a new type of a diphase opposition giant magnetostrictive self-sensing actuator is introduced. A bridge analysis model based on variable inductance is established. Dynamic balance separation technology for the giant magnetostrictive self-sensing actuator comes true by the least means square (LMS) self-adapting algorithm. The scheme design of one important part of the circuit with the real-time separation circuit of the dynamic balance signal based on a digital signal processor is obtained. The part of the signal separated circuit is designed, which includes logarithmicantilog practical multiplication circuit, amplifying circuit, filter circuits, and amplifier circuit. Based on the embedded system simulation software—PROTUES, the simulation effect of the circuit that separates the sensing signal from the mixed signals is obvious, which indicates that the circuit can rapidly and stably work. Moreover, the structure is simple, reliable, and meets the practical requirement.