面向电容式微机械超声换能器器件的32通道收发 电路设计与测试*

针对以电容式微机械超声换能器(CMUT)阵列为探头的超声成像系统,设计了一种兼具现场可编程门阵列(FPGA)控制、脉冲驱动以及微弱电流信号检测功能的电路。利用FPGA产生64路控制信号,控制脉冲信号的频率、脉冲个数、占空比等参数;脉冲电路在FPGA以及直流电压的控制下,产生32路脉冲信号;接收电路通过跨阻放大结构实现32路电流信号检测;32通道收发电路利用脉冲产生芯片内自带的T/R开关进行高压隔离。通过搭建测试平台,对收发电路功能及一致性进行测试,并连接CMUT进行自发自收测试。测试结果表明,32通道收发电路具有良好的一致性,电路可以实现基于CMUT阵列的32通道超声信号的发射,检测回波信号,并对CMUT器件的带宽进行测试。电路具有功能完善,结构稳定的优点,为基于CMUT阵列的超声成像系统的应用提供了硬件支持。     

基于FPGA和DSP的超声波风向风速测量系统

本文研究了数字化超声风速测量系统,提出并实现了完整的系统设计方案。该方案的核心是基于现场可编程门阵列(FPGA)和数字信号处理器(DSP)的硬件系统架构和基于包络重心法的信号处理算法。该设计可实现超声信号的高速数据采集和复杂的信号处理算法。测试结果表明所实现的超声风速测量系统具有体积小、反应速度快、抗干扰能力强和分辨率高等优点,且具有成本优势,并保持较低的功耗。     

野战有线通信系统二线全双工接口测试电路设计

野战有线通信系统全双工接口在单对线上同时收发信号,难以直接进行数据采集和测试。针对上述问题,研究了一种基于收发分离和自适应回波抵消的二线全双工接口测试方法。首先,设计电子收发分离器,实现线路上收发信号的隔离;然后,使用自适应回波抵消器,完成了近端回波干扰信号的抵消;最后,借鉴软件无线电技术和存储测试技术,构建测试系统,实现激励信号生成与数据采集。仿真和实验表明,该测试方法能够实现有效完成收发信号隔离以及回波干扰信号抵消,适用于野战有线通信系统二线全双工接口测试。     

基于3G-ASCX的小型飞行器异常导航信号检测系统设计

传统方法在异常导航信号信噪比较低时对小型飞行器异常导航信号的检测效果不理想。设计并实现了一种基于3G-ASCX的小型飞行器异常导航信号检测系统,硬件设计时着重于ASCX传感器模块、异常导航信号检测模块、主控基站模块、3G/GPRS传输模块的研究,3G/GPRS传输模块的硬件设计中,通过功耗低体积小的CC1100完成异常导航信号的收发,传输过程中通过芯片STC12C5410AD完成电容的平衡转换,选取了MC3486进行电压的转换,最终实现异常信号数据的安全快速传输;软件设计中,系统软件流程设计及异常导航信号检测模块软件设计,最后进行仿真实验,实验结果证明,相比传统系统,所设计系统检测到的小型飞行器异常导航信号同实际测量的异常导航信号具有较高的匹配度,与实际值相比,误差小于1dB,适合推广使用。     

便携式近红外漫反射中药质量监控仪的研制

介绍了便携式近红外漫反射中药质量监控仪的设计思想、基本结构、测试条件和使用方法。该光谱仪具有体积小、重量轻、成本低等特点,现场监控中药质量是非常便利的。     

基于MCS1210的便携式数字血压计的设计

为提高血压测量的抗干扰能力,提升测量准确性和简化操作,本文利用示波法检测血压的原理,提出了一种便携式数字血压计的设计方案,并进行了主要由微控制器、充放气控制、压力采集、信号调理、人机交互、实时时钟、电源等模块构成的系统架构设计。设计的主要方法是微控制器控制气泵给袖带充放气,袖带压力信号经调理后分离出静压力信号和脉搏波信号,送A/D转换、滤波处理,根据傅里叶拟合法计算收缩压、舒张压等数值,并通过LCD进行血压测量值显示。测试结果表明,该系统具有测量精度高、便携式的特点,具有一定的市场推广价值。     

一种多通道超导测试系统的设计与实现

为了实现对超导带材和超导电力装置的电压、电流、温度等信号的快速精确测量,设计了一种超导测试系统的方案并进行了实验验证。该测试方案是根据超导电力实验特点,并基于系统开关、数字万用表和电源等现有仪器,在虚拟仪器环境下,实现了超导体多路测试量的实时采集与远程监控。实验结果表明,该测试系统可以快速准确探测电气信号,为超导体的交流损耗、稳定性裕度等测量提供可靠的前提条件。     

瞬态微光探测系统逻辑控制设计与实现

提出一种系统探测的逻辑控制方案．该方案以FPGA设计技术为核心，基于模块化编程思想，实现整个系统的逻辑控制功能．通过计算机仿真和实际电路测试，给出ens、ad_elk、oe、hbe等关键信号的逻辑时序仿真和测试波形．信号处理通道转换、电路延时、功耗等指标分析与测试表明，设计具有实时性、高集成度、高可靠性、低功耗和灵活性等特点．     

一种基于单片机无线收发系统设计

设计一种基于STC89C51单片机的无线收发系统,本设计采用频率合成技术、FM调制技术及超外差解调技术,单片机对锁相环本振频率(发射43MHZ、接收53.7MHZ)锁定并通过液晶显示,本振频率在一定的范围内可调。将音频信号、咪头信号和数字英文字母信号作为调制信号,最后实现了音频、数字、英文字母等信号的重现。     

一种组合式甚高频全向信标和仪表着陆系统信号模拟器研制

针对传统的甚高频全向信标信号模拟器和仪表着陆系统信号模拟器智能化程度低、可靠性不高、携带不方便的缺点,设计了一种体积小、功耗低、精度高的组合式甚高频全向信标和仪表着陆系统信号模拟器。采用数字信号处理技术由FPGA完成多种音频调制信号的合成,利用具有幅度调谐功能的DDS合成载波信号,使用组合衰减技术实现输出电平在大范围内连续可调,满足了甚高频全向信标及仪表着陆系统信号格式及输出需求。信号模拟器实现了甚高频全向信标、航向、下滑与指点信标的信号模拟。整机性能经测试符合技术指标要求,现已经小批量推广应用,市场前景很好。     

Active noise control in a duct by an analog neural network circuit

Conventional active noise control (ANC) in ducts has been realized with digital signal processing. The physical size of the conventional ANC systems is usually large owing to the signal processing interval, and the cost of the system depends on the price of the digital signal processor (DSP). This paper proposes a new ANC system with an analog neural network circuit, which will process signals in short time periods without DSP. The proposed neural network circuit has a simple structure consisting of analog multipliers and an integrator, and we simulated the performance of the circuit by HSPICE. We also fabricated a circuit connected to a real duct and confirmed operation of the proposed ANC system.     

Simple Analog Complementary Metal Oxide Semiconductor Circuit for Generating Motion Signal

We proposed in this study a novel analog complementary metal oxide semiconductor (CMOS) circuit for generating a motion signal when an object moves, which is a simple structure. The proposed unit circuit was constructed using a previously proposed edge detection circuit and a novel proposed circuit for generating a motion signal which accepts an edge signal. The part for generating the motion signal was constructed using six metal oxide semiconductor (MOS) transistors and one capacitor. Results obtained by the simulation program with integrated circuit emphasis (SPICE) and the measured results of a test circuit constructed with discrete MOS transistors and the test circuit fabricated with a 1.2 μm CMOS process showed that the proposed unit circuit can output pulsed current (motion signal) when an object moves on the circuit. It was clarified from the SPICE results that the two-dimensional network constructed with proposed unit circuits can output motion signals. The size of the novel unit circuit is expected to be about 110 × 110μm² obtained by the 1.2 μm CMOS process. It is possible to arrange 90 × 90 unit circuits on a chip which has an area of 1 × 1cm². The aperture ratio is expected to be about 21%, which is twice as large as that of the previously proposed circuit. An integrated circuit for image processing in real time can thus be realized by applying the two-dimensional network constructed with the proposed circuits.     

A New Coplanar Design of Multiplier Based on Nanoscale Quantum-Dot Cellular Automata

Quantum-dot cellular automata (QCA) nanotechnology is emerging as a replacement technique for maintaining increasing microprocessor performance and it yields small size, high speed, and low power consumption. On the other hand, a multiplier is a circuit that multiplies two binary values for performing sequential addition operations and accumulating the results. This type of circuit is the basic structural unit of many arithmetic logical units, digital signal processing, and communication system. The multiplier circuit contains some full adders that can perform add operations, so, it is very important that low-complexity full adders are used. Therefore, in this paper, a new 2 × 2 array multiplier circuit in QCA by employing an efficient structure of full adder is designed and implemented. This design is constructed using coplanar layouts and compared its performance with existing QCA multipliers. The operation and efficiency of the proposed structure have been confirmed using QCADesigner tool. The simulation results have demonstrated that the 2 × 2 multiplier leads to less cell count and area as the prime designing factors.

     

基于金属氧化物半导体晶体管Colpitts混沌振荡电路及其同步研究

用金属氧化物半导体(MOS)晶体管模型取代传统Colpitts混沌振荡电路中的三极管模型, 提出了一种基于MOS管的Colpitts混沌振荡电路. 通过合适的归一化方法, 得到了与基于三极管电路类似的状态模型. 平衡点的指标说明两种结构产生混沌的机理并不相同. 然后, 通过参数反演, 得到了详细的电路参数, 并用Pspice软件仿真得到了混沌吸引子和混沌信号的频谱图, 说明了此结构可在低电压下工作并且能产生高频率的混沌信号. 最后, 用误差反馈的方法实现了这种结构的同步. 关键词： Colpitts混沌 金属氧化物半导体晶体管 低电压 误差反馈同步     

Multistage opto-neuromorphic process system based on commercial optoelectric devices

This paper proposes a structure for opto-neuromorphic processes by using multistage connections of photo-transmitters. The basic unit consists of a light-emitting diode and a photoresistor for a non-inverting photo signal processor. By constructing a cascade structure of these basic units, multistage photo transmission of input light signal is examined in pulse signals with various periods and duty cycles as the input to the first opto-neuromorphic stage. This approach verifies that optical signals can be transmitted through our proposed structure and that by controlling the amount of the transmitted light between the basic units, the gain between stages can be controlled. It is demonstrated that this structure can be used for opto-neuromorphic processes by transmitting light signals as if transmitting signals between neurons with different weights and activation patterns. The proposed structure can be modified with an inverter circuit to build a photo-inverter and by using a combination of photo-transmitter and photo-inverters, it can serve as the basic structure to build more complicated opto-neuromorphic process systems.     

基于SRIO传输的高速时钟电路的优化设计

随着系统电路工作频率的不断越高,在应用中对系统互连和电路间的时钟提出了更高的要求。针对在某信号处理系统的设计中,在测试中偶尔出现SRIO链路异常问题,对高速时钟的参数进行了深入分析,发现了时钟信号受到热噪声的影响引起时钟抖动,会导致SRIO链路断开。提出了增加时钟信号的过渡斜率的优化方案,改善了时钟信号的品质,试验证明系统工作稳定可靠,达到了预期效果。     

基于相关双采样的线阵CCD信号采集电路设计

针对CCD信号相关双采样（CDS）难于实现的问题,介绍了一种简单实用、易于实现的线阵CCD信号相关双采样电路。该电路采用CPLD、AD9844实现了线阵CCD时序驱动、信号相关双采样、自动增益、A／D转换等一体化设计。实验表明,设计的采集电路能有效地消除复位等多种噪声的影响,实现对背景光的自适应调整,达到提高信噪比,改善视频图像的目的。     

基于衰减振荡信号特征参数和伪阻抗的电路参数计算方法

本文研究了基于暂态信号中衰减振荡信号的电路参数计算理论和方法.在电力系统线路发生故障时,通过计算暂态信号流通路径电路参数可确定故障位置、推断故障原因,而衰减振荡信号作为暂态信号主要成分,因此分析基于衰减振荡信号的电路参数计算在电力系统故障定位中有重要理论价值和实际工程意义.结合R-L电路和R-C电路,首先推导了时域衰减振荡电压、电流信号特征参数与各元件参数以及电路参数间定量关系;并分析了电路在衰减振荡信号下阻抗特性,结合稳态正弦分量阻抗概念,将电路流经衰减振荡信号时的阻抗特性定义为伪阻抗,并确定了伪阻抗与电路参数和信号特征参数间的关系;同时分析了串并联条件下伪阻抗与元件参数关系.以此为基础分别提出了基于信号特征参数和基于伪阻抗的电路参数计算理论,结合现有衰减振荡信号特征提取方法,提出具体计算方法,为基于衰减振荡信号的电路参数计算理论发展以及实际工程应用奠定了重要基础.通过MATLAB模拟产生故障信号对所提理论和方法进行验证,结果证明了所提理论和方法的正确性和准确性,并以实际电网故障信息为基础,基于PSCAD/EMTDC建立实际配网模型并对实际单相接地故障进行重现,对配网单相接地故障进行定位分析,结果证明了方法的可行性.     

Compact NRD-Guide Switch by Using Schottky Barrier Diodes

Based on a miniaturized NRD-guide coupling structure, a new switch circuit is proposed. The 3dB coupler and two schottky barrier diodes with improved diode mounts and matching circuits are used. It features with wideband performance and compact size. The high isolation performance can also be realized using the same circuit by adjusting the bias currents of the diodes. An experimental prototype is implemented and the tested characteristics are supplied.     

Research on front-end electronics gain compensation of MCP imaging detector北大核心CSCD

基于微通道板电子倍增电荷分割型阳极的成像探测器常用于行星大气、气辉等微弱信号探测。针对探测器读出电路增益不相等导致探测器成像产生畸变的问题,利用理论分析结合MATLAB仿真揭示了不同畸变图像的形成机制,在该基础上提出了一种探测器读出电路增益补偿方法减小探测器成像畸变。通过MATLAB仿真和实验测试结果表明该文提出的方法能够有效减小由于读出电路增益不相等导致的探测器成像畸变。