基于锁相技术的微机械陀螺闭环驱动电路

传统的闭环驱动电路其输出信号的频率与微机械陀螺驱动方向的固有频率存在一定偏差,且频率抖动较大,系统的建立时间较长．基于上述不足,在分析微机械陀螺闭环驱动方式工作原理的基础上,提出一种基于锁相技术的闭环驱动电路方案,电路进入稳定工作状态时,交流驱动电压与驱动方向敏感电流的相位及频率一致．微机械陀螺在驱动方向谐振,显著改善了输出信号的频率特性．仿真结果表明,这种闭环驱动电路输出信号频率与微机械陀螺驱动模态固有频率完全一致,频率抖动及系统建立时间分别是传统闭环驱动电路的38％和50％．通过实验验证了该方法的可行性     

Zeeman激光双模稳定的研究

本文从理论上和实验上认证Ｚｅｅｍａｎ激光输出双模频差的不稳定因素，阐述了利用激光输出的左右旋光光强相等控制双模频差的热稳定系统及实现方案，并作了简要的精度分析。     

基于FPGA和DSP的激光陀螺信号处理电路设计

研究机械抖动激光陀螺的信号读出系统,设计激光陀螺的信号处理电路。光电转换后的微弱电流信号经过前置放大电路转化为电压方波信号,在FPGA中进行鉴相解调以及可逆计数,最后由DSP实现机抖偏频解噪和低通数字滤波。与激光陀螺联合测试并将结果输出至上位机,结果表明设计的电路实现了对激光陀螺输出信号的有效采集,满足激光陀螺功能测试的需要。     

驱动刚度非线性对双检测微陀螺性能的影响

驱动刚度非线性的存在会导致幅频曲线出现典型的非线性硬化特性,从而影响双检测微陀螺检测输出信号和灵敏度的稳定性。为对比线性刚度和非线性刚度对微陀螺检测输出的影响规律,首先求解线性刚度下系统的稳态响应,其次采用多尺度法求解非线性动力学方程的近似周期解,并考虑科氏力对检测输出的影响,在此基础上探讨驱动刚度立方非线性对双检测微陀螺系统主共振的幅频曲线、共振频率、灵敏度的影响规律。研究发现:驱动模态共振频率与刚度非线性及振动峰值密切相关;刚度非线性越强,固有频率的漂移量对振幅的变化就越敏感。较弱的驱动刚度非线性就会导致检测一和检测二在驱动模态频率处的幅值大幅下降,由此对微陀螺的输出信号产生极大影响,降低了微陀螺检测信号的稳定性,并与基于线性设计的灵敏度值产生极大的偏差。     

基于扫频技术的乐甫波器件测试系统

介绍了乐甫波器件的结构,设计制作了乐甫波器件,给出了乐甫器件的制作参数,搭建了基于扫频技术的测试系统,包括信号源模块、信号采集模块、微控制器模块等.通过DDS芯片AD9912在一定频率范围内,以一定频率间隔扫频输出高频正弦激励信号,利用AD8302芯片测量扫频范围内每一频率点的器件输入激励信号与输出响应信号幅值比,描绘出幅频特性曲线,并给出器件谐振频率.该测试系统的测量结果与网络分析仪基本一致,实现了网络分析仪的扫频功能.     

一种新型激光陀螺的检测方法

本文通过对新型四频差动激光陀螺输出信号的分析,给出了一种适应新型四频差动激光陀螺输出信号的检测方法。通过APD和高频低噪声前置放大器实现光电接收,通过集中选频放大电路进行滤波和放大,然后采用模拟乘法器实现自乘检波,并根据该方法设计了实际的检测电路。采用直管四频激光器的背向输出来模拟新型四频差动激光陀螺的输出,对电路进行了实际测试。通过测试,验证了检测电路方法的可行性。     

基于FPGA的硅微机械谐振式陀螺仪数据采集系统设计

介绍了一种硅微机械谐振式陀螺仪的结构,给出了调制系数或最大频偏与输入角速度成正比的关系.通过对陀螺仪敏感质量块静电驱动力和双端音叉谐振器输出信号的分析,得出了双端音叉谐振器输出信号的相位差与调制系数之间的关系.提出了一种调频信号最大频偏的检测方法,通过此相位差的计算得出调制系数或最大频差,进而计算出输入角速度的值.设计了一种基于FPGA的数字化解调方案,给出了基于FPGA的数字化最大频差测量电路的测试结果.结果表明测量电路对最大频偏有很好的测量效果.     

基于DSP的测控系统设计

描述了基于DSP(数字信号处理器)的测控系统各模块的硬件设计实现,设计了以TMS320F28335为核心,加外部模数转换器和内部捕获单元实现三轴陀螺,双轴加速度计5路信号的采集系统,结合GPS(全球定位系统)和无线传输模块的目标信息和实时位置信息,经DSP处理后输出PWM信号,再经光电隔离后实现对舵机的控制.试验结果表明:采用了TMS320F28335芯片后,不仅简化了系统外围设备,降低了系统的功耗,而且提高了系统的准确性和实时性.     

一种基于DSP的交流信号频率检测系统

本文设计了一种交流信号频率检测的系统。即通过对交流信号的采集,并借助DSP来实现对模拟交流信号进行和数据采集、运算、分析和处理。系统的硬件部分主要由DSP处理器、AD采样电路、信号调理电路以及液晶显示部分构成,软件部分主要是基于DSPTMS320VC33的C语言程序,包括系统的初始化、AD采样子程序、FFT运算程序等。本系统能够实现对交流信号在频域内精确的分析计算。最后利用液晶显示测试结果。     

机抖激光陀螺稳频控制技术

激光陀螺的工作中心频率作为激光陀螺的工作计量基准,其频率的稳定性对激光陀螺的测量精度有着直接的影响．稳定激光陀螺工作中心频率最为有效的方法就是采用主动腔长补偿控制．在对腔长控制原理和方法介绍的基础上,提出了将激光陀螺输出光强信号进行交直流分量分离独立控制的方法,并给出了系统的硬件设计框图,最后介绍了软件设计流程．测试结果表明漂移均方差在0．4°·h-1以内,满足系统的使用要求．     

Optical signal processing in dual-wavelength optoelectronic drop analyzer

Dual-wavelength optical signals are injected into the liquid drop through optical fibers in order to study the light intensity variation during the drop growth. Modulation and demodulation are used to reduce the influence of ambient light on the valuable optical signals. HA17555 chip composes the oscillating circuit for light modulation, with different high oscillating frequency for different light source. The light signal collected by a fiber detector after propagation inside the drop is changed into electric signal through the OPA2111 photoelectric circuit. The second-order band-pass filter composed of MAX275 chip is used for signal-separation. The high-pass filter is used to prevent the low frequency signal of ambient light. The valuable signal related to the drop is demodulated by a linear demodulation circuit including a half-wave rectifier, full-wave composition and low-pass filter.     

Optical imaging with a directional detector

We demonstrate a new optical imaging technique based on a directional detector that measures the intensity of light waves that propagate only in a narrow angular window around a specific direction. Light waves that propagate in other directions do not significantly affect the detector output. The directional detector is obtained by illuminating the interrogated object with a high-coherence light source and measuring the interference between the light wave reflected from the object and a reference wave. By measuring the intensity of the interference pattern with an optical detector that has a finite width and moving the object by use of a rotation stage, one can obtain the angular directionality of the filter. The use of coherent detection in the directional detector makes it possible to increase the sensitivity of the system. The directional detector was analyzed theoretically and demonstrated experimentally for a Gaussian beam scattered from a conducting cylinder. The interference enabled us to theoretically increase the angular resolution by a factor of approximately 10 and experimentally by a factor of 8.5. A configuration for using a directional detector array to reconstruct a two-dimensional object is suggested. Since the directional detector makes it possible to reduce the effect of diffraction and scattering, reconstruction techniques based on nondiffracting sources, as implemented in x-ray tomography, may be used.     

压缩天然气(CNG)加气柱检定系统研究

以DSP(TMS320F28335)芯片为核心,采用高精度A/D对传感器的输出信号进行实时采集,结合现代信号处理算法,精确计算出相位差和频率,利用DSP快速运算功能,算出被测流体的密度和质量流量等信息,并在上位机上采用delphi语言开发用户界面,解决了大流量、高压力下信号的实时采集和流量变化幅度较大等难题。实验结果表明:该系统有效提高了系统的稳定性和测量准确度,大大缩短了系统的响应时间。     

星载 SAR 地面快视处理器距离预滤波的设计实现

综合孔径雷达(SAR)实时成像处理器, 在满足分辨率的情况下, 通过预滤波和降采样的方式降低数据率来满足系统处理带宽的要求. 距离向预滤波器由于其在整个信号处理机中的特殊位置决定了其需要极高的运算速度和良好的频响性能. 本文对其工作原理和实现方法作了介绍, 重点比较了采用 TS101 DSP 和 XC4VSX35 现场可编程门阵列(FPGA)实现该高性能滤波器的异同, 并得出采用 FPGA 比采用 DSP 具有无法比拟优势的结论, 本设计工程验证的结果说明了设计的合理性.     

基于DSP的频谱分析型激光多普勒信号处理器的研究

为了提高激光测速系统中信号处理速度,获取更高的测量精度和实时检测能力,本文从硬件结构、传输策略和试验结果入手,提出了利用DSP芯片作为频率分析处理器的多普勒测速系统.通过对A/D控制策略,光电数据采集压缩,DMA传输和DSP处理器中的FFT谱分析和频谱校正算法的研究和对数变频模式模拟电压信号测量试验,实现了多普勒信号处理器在显示采样频率为7MHz,速度显示间隔为0.3ms的实时检测和频率细化能力.     

基于EDA技术的图像边缘检测协处理器的设计

在嵌入式图形系统处理领域,图像处理的速度问题一直是一个很难突破的设计瓶颈.文章在介绍一种全新的DSP CPLD图像处理系统工作原理的基础上,阐述了一个基于EDA技术的、用FPGA实现的800×600像素的图像边缘检测协处理器的设计,包括边缘检测算法选择、系统的FPGA实现设计和有关仿真结果等.该协处理器的像素处理方式采用全硬件并行及流水线技术,比单独采用单片机和DSP的系统,其处理速度分别提高了400倍和10倍,同时该系统集成在一块集成芯片上,体积小,功耗低,可靠性高,并可现场编程,在线升级.     

侧壁四电极电容耦合非接触电导检测器(英文)

研制了一种集成于硅基电泳芯片分离沟道末端侧壁的新型四电极电容耦合非接触电导检测器.研究了该电导检测器的等效模型,对等效电路模型中的参数进行了公式推导,并讨论了影响电导检测响应灵敏度的相关因素.采用深刻蚀及离子注入加工技术制得了用于电导检测的立体电极.制作了基于锁相放大原理的信号处理电路,对该电导检测的频率响应及灵敏度进行了测试分析.实验结果表明,当激励信号频率为300 kHz时,该电导检测器具有最佳线性度;不同浓度Na+溶液响应电压差值为5 mV;检测限达到10-8mol/L;且成功实现了Na+和Li+混合无机阳离子的电泳分离在线检测.     

基于生物电阻抗的血型检测新方法及系统实现

提出了基于生物电阻抗测量技术的血型检测新方法并研制了检测系统。该系统采用单片机结合AD9850芯片实现DDS技术产生激励信号,设计椭圆滤波器消除信号干扰;运用低成本放大器AD8370设计稳幅电路,确保信号输出幅度不变;系统采用AD8302幅相检测芯片实现阻抗信息提取;基于人工神经网络判别红细胞悬浮液凝集强度,并结合判别规则得到血型结果。测试结果表明该系统精度高,稳定性好;临床实验表明,该系统能正确识别红细胞6种不同凝集程度,能100%正确地检测出正常标本的ABO和Rh血型,可更好地满足临床需求。     

Direct bidirectional angle-insensitive imaging of the flow signal intensity in Doppler optical coherence tomography

We introduce a new method, to our knowledge, for direct detection of flow signal intensity by stationary target rejection. In our system, two delay lines are constructed with identical scanning speed and ranging depth. One delay line is used for depth ranging as well as phase modulation, and the other one acts as a full-range retroreflector (FRRR). The signal from this FRRR carries the overall features of local phase modulation, and it is used as the local oscillator for coherent demodulation. With this setup, stationary targets can be rejected at a 4-kHz high-pass cutoff frequency of the filter that follows the demodulator, compared with 20 kHz for conventional fixed-frequency demodulation. This technique features angle insensitivity and provides flow direction as well by implementing standard in-phase and quadrature detection. Besides the direct directional detection of flow signal intensity, flow speed information can be acquired with postprocessing.     

Laser-induced fluorescence detection system for microfluidic chips based on an orthogonal optical arrangement

In this work, a simple LIF detection system based on an orthogonal optical arrangement for microfluidic chips was developed. Highly sensitive detection was achieved by detecting the fluorescence light emitted in the microchannel through the sidewall of the chip to reduce scattered light interference from the laser source. A special crossed-channel configuration, with a 1.5-mm distance from the separation channel to the sidewall of the glass chip, was designed in order to facilitate collection of emitted fluorescence light through the sidewall. The significant difference in intensity distribution of scattered laser light on the chip plane observed in this study was fully exploited to optimize S/N ratio of detected signals by rejection of scattered light, both through systematic measurements and employing ray-tracing simulation. A fluorescence collection angle of 45 degrees in the chip plane gave the best result, with a scattered light intensity 1/38 of that obtained at an angle of 90 degrees. Sodium fluorescein and fluorescein isothiocyanate-labeled amino acids were used as model samples to demonstrate the performance of the LIF system. A detection limit (S/N = 3) of 1.1 pM fluorescein was obtained, which is comparable to that of optimized confocal LIF systems for chip-based capillary electrophoresis. Apart from the high detection power, the system also has the advantages of simple optical structure, compactness, and ease in building.