带GPIB直流数字电压表程控电路的设计

PZ66型直流数字电压表是带通用接口的高精度直流数字电压表。精度±0.005％;分辨力:1μV;六位显示。设有以下接口功能:源挂钩功能(SH_1);受者挂钩功能(AH_1);讲功能(T_1),包括串行点名功能(SP);听功能(L_2);服务要求接口功能(SR_1);远地/本地接口功能(RL_2);器件触发接口功能(DT_1)。 PZ66于1983年9月经部级鉴定通过。1984年投入批量生产。本文介绍程控电路的设计与计算。程控电路把测量电路的数字部分与通用接口功能部分连接起来,实现整机的可程控。     

FPGA实现海德汉绝对式编码器与上位机的智能通讯

为实现EnDat绝对式编码器与上位机之间的通讯,采用现场可编程逻辑器件(FPGA)设计一种EnDat 绝对式编码器通讯接口.该接口主要由RS-485收发芯片、光电隔离电路、可编程逻辑器件FPGA组成.根据FPGA模块化设计特点,把FPGA内部处理电路划分为若干功能模块,分别对这些模块进行设计,完成对编码器输出信号的串并转换、CRC校验等功能.实验结果表明:基于FPGA所设计的智能通讯接口能够实现EnDat绝对式编码器与上位机之间的通讯.     

基于FLEX20K器件的采样电压测量系统的研究

传统的数字系统通过设计线路板实现系统性能,而可编程器件是通过设计芯片内部的互联逻辑来实现系统功能.文章采用在系统可编程器件FLEX20K和一个模数转换器ADC0809以及外围显示数码管,在MAX PLUS Ⅱ开发软件环境下,采用VHDL语言,实现了对0-5V范围的采样电压测量系统.模数转换器在接口控制模块的作用下,将输入的模拟信号转换为8位二进制数字信号;然后通过存储器将其转换为相应大小值的七段显示码,送到显示电路中,显示转换后数据值.系统功能经过验证,测量结果符合ADC0809的精度要求.该系统中除A/D转换器和数码管是对应的外围器件,其余所有电路都集成在可编程器件FLEX20K上,可以使系统在不改变整体结构的基础上,进行扩展和维护.     

电力系统物理与数字联合实时仿真

提出了结合物理模拟与数字仿真实现电力系统联合仿真的技术.以替代定理为基础阐述了联合仿真的理论基础,并提出了联合仿真系统的总体布局.数字仿真接口用A/D转换通道与受控注入电流源实现,物理仿真接口用基于直流耦合的背靠背变流器结构的放大电路实现.最后通过实验验证了该技术的可行性.     

基于FPGA的惯性导航系统设计

本文采用FPGA开发了一种嵌入式低成本的惯性导航系统,通过对硬件结构的描述分析了系统中各个电路模块的功能,给出了各个模块的实现方法.结合惯性器件的接口方式,给出了FPGA接口的实现方法,实现了NIOS2集成开发环境下获取惯性器件的C程序.最后,实验证明本方案可行.     

PXI高精度数字万用表的设计与实现

介绍基于PXI接口的五位半数字万用表模块的设计与实现方法.该模块以ES51966为核心,ARM单片机(LPC2103)为控制器,实现了各种电参量的高精度测量以及对测量数据的处理与收发控制,并通过专用PCI接口集成芯片PCI9054实现了PXI接口,从而实现与上位机的通信.本文重点介绍硬件电路的设计思路、驱动程序的设计流...     

单边电源模数变换电路

本文介绍单边电源模数变换计算机接口电路。该电路由单边电源运放LM358和四比较器LM339等元件构成,其输出数字量经光电隔离器件与计算机隔离。     

一种高速VXI消息基接口的设计

VXI总线作为新一代测试与测量总线被广泛采用,接口性能的优劣往往直接影响整个测试过程.本文在利用可编程逻辑器件实现VXI消息基接口的基础上,针对常用VXI接口数据传输速度慢的问题,提出了一种采用FIFO设计数据传输通道,实现高速数据传送的方法.本文重点对高速VXI接口的硬件电路、监控软件以及仪器驱动器的实现方法进行了详细讨论,并给出了实验数据和应用结果.     

以太网接口设计

为开发数字中频接收机的以太网接口,在基于DSP和FPGA的数字中频接收机系统板上应用专用网络接入模块IIM7010,通过设计相应的接口电路和驱动程序,实现以太网通信.这种应用可以使系统设计者不必关心繁琐的网络接入协议,比较简洁地实现数字中频接收机的以太网接入.     

自适应测量接口的研究和实现

针对目前测量接口的不足,本文提出了集增益和量程自适应于一体的智能自适应测量接口.首先利用多路模拟开关及驱动电路组成衰减电路实现量程自适应;其次由数字电位器与仪表放大器组成程控增益放大器实现增益自适应;最后由采集模块进行数据采集及单片机处理数据并显示结果.实践表明,本文设计的自适应测量接口智能化程度高、输入信号动态范围宽、硬件电路简单实用、成本低.     

基于MSP430单片机的多路电气量检测装置的设计

介绍了一种多通道电气量检测装置。该装置以单片机MSP430F1611为核心,由电源、模拟信号调理、数字信号输入、串行通信接口、人机交互接口及继电器输出接口电路组成,可获取研制新型剩余电流保护装置的实验数据。该装置电路结构简单,操作方便,易维护。     

基于CPLD的数字交流伺服系统接口设计

为了解决伺服系统的接口电路结构复杂和可靠性低的问题,研究了一种基于CPLD的接口设计方法;通过对CPLD编程完成大量的逻辑电路设计,简化了接口电路。本设计在工程项目中得到应用,获得了较好的运行效果。     

采用计算机实现直流电动机时间常数的数字化测试

介绍通过计算机的接口电路对电流与转速信号进行采集、处理 ,应用VC+ + 语言制作可视化界面 ,显示电流与转速的响应曲线及电磁时间常数与机电时间常数测试数值 ,实现了数字化的测试方法。该方法简单易行、测量精度高。     

旋转变压器在数字伺服舵机系统中的应用

设计完成了一个采用旋转变压器检测舵反馈的数字伺服舵机系统,使用一款用于电机控制的SOCG105作为系统的控制核心,介绍了正余弦型旋转变压器的基本原理,设计了旋转变压器与G105的接口电路及相关外围电路,并利用G105内部的旋变解码模块实现舵面角位移的解算.试验证明,该方案简化舵机控制电路的设计,并能够精确地实现舵反馈的测量.     

A rapid prototyping environment for teaching digital logic design

In this paper, the authors present a rapid prototyping environment for teaching digital logic design. Their primary goal was to build an FPGA based hardware prototyping system that provides sufficient flexibility for the implementation and functional verification of various digital circuit designs. Since the system is intended to be used as an experimental and demonstration board to support digital design courses and practices for the undergraduate students, it is simple to use and completely supported by the software for automatic implementation of digital circuits. The prototyping environment consists of a PC and the programmable board composed of 3 FPGAs. One FPGA is used to implement the digital circuit, while the rest of the devices implement an interface between the digital circuit and the PC. The PC is used for designing a digital circuit, automatic generation of the interface logic, programming the FPGAs and as a test engine for functional verification of the designed circuit. The presented environment is used in the regular educational process and the sample student projects are summarized     

SSCSSC: a tool for the teaching of digital circuits

The authors present a computer program to support the teaching of digital circuits. The program is used to describe, synthesize, and simulate combinational and synchronous sequential logic circuits, and to help students in their first contact with automatic synthesis tools. The program runs on both MS-DOS and UNIX machines, and it can be given freely to students for home use to significantly reduce the crowding in laboratories. Care has been taken to provide a friendly interface, so that the user can immediately concentrate on the study of circuits instead of having to learn a new program. The software described by the authors is currently used as a support tool in the course on Digital Circuits for Electronic Engineers at the University of Pisa     

基于现场总线的分布式粮情系统温湿度检测的研究与设计

根据目前粮情管控系统中粮仓温湿度测量存在的问题,设计出一种基于现场总线分布式的粮情管控系统粮仓温湿度测量电路。利用单总线数字技术,接口电路及调整电路,并采用组态王6.53软件进行仿真试验。试验结果表明,该温湿度测量电路能使基于现场总线分布式粮情管控系统成本降低、测量精度提高、抗干扰性能增强、线路简单、安装维护方便等优点,满足了实时测控和管理的要求。     

CPLD与16C554在航空发动机参数采集器中的应用研究

依据高性能和小型化的要求,阐述了DSP在航空发动机参数采集器硬件系统设计中的应用。以TMS320C31DSP为处理核心,采用复杂可编程逻辑器件(CPLD)对外围扩展电路(A/D、串口扩展芯片16C554和外部存储器等)进行片选和中断控制,从而提供了丰富的模拟接口、方便灵活的数字接口和串行通信接口。利用16C554扩展串口,其硬件接口电路简单;利用复杂可编程器件CPLD设计DSP扩展外设电路的译码电路,可以使设计者在系统内进行编程。本文给出了主要器件具体的硬件选型,并结合其特点阐述了它们在航空发动机参数采集器中的硬件连接及软件操作方法。     

Microcontroller based digitally controlled ultrasonic motor drive system

Piezoelectric driven ultrasonic motors have been attracted as considerable actuators for the servo speed and position applications in recent years. These motors have important features and advantages to be preferred in the special movement applications. Ultrasonic motors have different operating principles and different drive and control systems than the electromagnetic motors. In this study, microcontroller based digitally controlled drive system has been proposed for a travelling-wave ultrasonic motor. Drive system includes power circuit, interface electronics circuits and microcontroller parts. Power circuit is combined from half-bridge serial-resonance inverter to provide highfrequency two-phase voltages. Interface circuits include gate drive, direction control, opto-coupler and filter circuits. Microcontroller is programmed to generate required digital control signals for overall control of the motor. Related to the reference speed, the microcontroller generates control signal resulting proper driving frequency. Consequently, the actual motor speed tracks the reference speed precisely. The speed feedback is taken from optical encoder and transmitted to the controller as digital speed and position signals. The developed drive system has been tested experimentally. The obtained results show the effectiveness and reliability of the proposed system. The microcontroller based drive system can be applied easily and successfully to the ultrasonic motor.