基于CPLD+LVPECL可调窄脉冲发生器的设计与实现

采用CPLD和具有速度极快的LVPECL门电路来实现脉宽可调的窄脉冲信号。利用CPLD提供的10 MHz激励信号和对延时芯片进行写延时控制字来产生所需脉宽。测试结果表明,该可调窄脉冲发生器能产生500 ps～20 ns范围内的脉宽可调、幅度约为400 mV的脉冲信号。     

远程控制高时间分辨多通道脉冲发生器设计

基于FPGA为四分幅相机研制了高时间分辨的多通道脉冲发生器;该系统具有4个独立的输出信号,配合高压快门电路实现对分幅相机4个通道曝光时间和延迟的控制;采用FPGA内部计数方法实现各个通道输出脉冲的宽度和延时的精确调节,同时采用光纤通信的方式实现远程控制,并利用高速高压输出驱动接口提高了系统的输出能力;研制的同步脉冲发生器最小时间分辨可达4 ns、输出幅度可达7.5 V、传输距离大于10 km。     

多通道虚拟信号发生器的设计与实现

本文介绍一种多通道虚拟信号发生器的设计和实现 方法,该信号发生器采用“计算机＋PC总线模板＋软件”的模式进行设计,拥有众多的信号通道,便于在需多信号源的测控系统模拟装置中使用。     

基于PCI-E总线的高速多通道信号发生器设计

针对现代水声定位系统性能检测需求,设计了一种基于PCI-E总线的高速多通道信号发生器;利用PC机LABVIEW软件生成不同的电模拟信号,通过PCI-E总线板卡输出到信号发生板,实现信号高速稳定传输;以FPGA为核心控制器,利用PCI9054桥芯片实现本地总线转换,经过DA逻辑控制以及多通道模拟电路调理,最终完成多通道信号波形输出;经测试系统功能稳定,达到了指标要求;该设计结构简单,可扩展性强,具有广阔的应用前景,目前已成功应用于某水声定位系统实验室功能检测.     

多通道虚拟信号发生器的设计与实现

本文介绍一种多通道虚拟信号发生器的设计和实现方法，该信号发生器采用“计算机 PC总线模板 软件”的模式进行设计，拥有众多的信号通道．便于在需多信号源的测控系统模拟装置中使用。     

用555时基电路制作脉冲宽度,频率可调的脉冲发生器

用５５５时基电路制作脉冲宽度、频率可调的脉冲发生器吉林大学姜殿武，赵玉山自从５５５时基电路问世以来；由于成本低、应用广泛、稳定性高，深受电子工作者的欢迎。５５５时基电路作为ＲＣ振荡时间电路有较高的精度和稳定性，而且外围元件少，带负载能力强，并可直接驱...     

基于PC机的参数可调正弦信号发生器的设计

在生物电磁实验中，频率、幅值独立连续变化的正弦波信号源是低频交变电磁场必不可少的信号发生装置。单纯由硬件组成的装置，结构复杂，可控性较差。文章提出了一种基于PC机的参数可调正弦波发生装置，通过软、硬件的结合，既可以实现波形参数的独立连续变化，又具有良好的人机对话界面，原理简单，使用方便。实验证明，用该方法实现的参数可调正弦信号发生器，输出波形平滑规则，频率、幅值变化范围较大，具有较强的实用性。     

多路编码脉冲发生器

本文介绍一种采用８０３１单片机的信号发生器，能输出多达４路的脉冲或编码脉冲信号，脉冲的重复周期、编码由键盘置入，并通过ＬＥＤ显示。     

相位差可调的双通道信号发生器的设计

为了调节两路相同频率正弦信号之间的相位差,采用DDS技术设计了相位关系可调的双通道信号发生器。该信号发生器的输出频率范围为0Hz～150MHz,频率分辨率为1滋Hz,相位调节范围为0°～360°,分辨率为0.022°。它不仅可输出两路相同频率、相位差可调的正弦信号,而且可分别作为两路独立的可调频、调幅、调相的信号发生器使用。     

一种正弦信号发生器的设计

介绍了一种正弦信号发生器。系统由SPCE061A单片机产生命令控制字和10kbps码元,AD9850产生正弦信号和FM信号,利用模拟开关4051实现调制度ma的程控和ASk/PSK信号。该系统具有波形失真度小、频率范围大且稳定、步进选择多等特点。     

基于单片机的高压脉冲发生器的设计

本文设计的基于单片机的高压脉冲发生器,可用来产生脉冲宽度、脉冲个数、脉冲电压强度均可调节的高压脉冲电场.文中给出了其主电路及控制电路各部分的电路结构.     

基于多配置LFSR的测试生成结构设计

针对内建自测试技术中传统的测试生成故障覆盖率过低、硬件开销过大等缺点,提出了一种多配置LFSR的混合测试矢量生成结构,结构利用矩阵理论先后对随机性矢量和确定性矢量进行反馈网络的配置;针对确定性矢量的生成,提出了一种反馈配置解的寻优算法,在一定程度上减少了硬件开销,因结构生成的混合测试矢量可以同时检测出被测电路中的随机矢量可测性故障和抗随机性故障,进而保证了测试故障覆盖率。最后,通过实例和对几种综合基准电路的测试,验证了该方案的可行性。     

数字化波形发生器的设计

介绍一种数字化波形发生器的设计。采用MAX038函数发生器芯片,在单片机的控制下输出正弦波、三角波、矩形波,频率、占空比可通过12位4路输出的数模转换器MAX526进行数控调节。波形的频率和幅值采用LCD显示。8选1多路模拟开关AD7501在单片机的控制下实现频段的选择。MAX038输出的幅值电压放大后送入数字衰减器AT-280进行衰减,以调整放大后的输出幅度。     

The design of a language processor generator

Language processor generators are systems that produce various language processors (including compilers) on the basis of a high-level specification. The design of language processor generators is discussed on the basis of experiments with a traditional compiler writing system (HLP78) employing pore LALR parsing and general attribute grammars. It is argued that these methods are too primitive from the practical point of view. The design of a new language processor generator, HLP84, is based on this view. This system is an attempt to provide high-level tools for a restricted class of applications (one-pass analysis). The syntactic facilities include regular expressions on the right-hand sides of productions, a disambiguating mechanism that is integrated with regular expressions, and a mechanism for using semantic information to aid parsing. The semantic facilities include automatic support for semantic error handling and for symbol tables. Early experiences with the new system show that in spite of the general overhead caused by the higher automation level, the system allows the generation of reasonably efficient processors.     

The design and implementation of a grammar-based data generator

DGL is a context-free grammar-based language for generating test data. Although many of the features of DGL are implemented in a straighforward way, the implementation of several of the most important features is neither trivial nor obvious. Before one can understand the implementation of these features, however, it is necessary to understand the overall structure of the compiler and its output, which was designed to be flexible enough to incorporate new features easily. Variables and chains are two of the most important features of DGL, and also two of the trickiest features to implement. The run-time dictionaires, which are built into the C code generated by the compiler, are implemented as pure code rather than as table-look-up routines. The compiler itself is reasonably straightforward, except for the expansion of character sets and compile-time macros. These two features can cause the ‘multi-dimensional’ expansion of a string, the implementation of which must be carefully designed.     

NMR pulse sequence generator for a PC driven spectrometer

This paper describes software devoted to the generation of NMR pulse sequences and which has been developed for a spectrometer under the control of a PC. It has been specially designed with the goal of upgrading early NMR spectrometers and represents a powerful tool for programming pulse sequences with an arbitrary degree of complexity. Its key features are: ease of use, flexibility, versatility and hardware independence. Moreover, an important use of graphism (allowing for the visualization of sequences) associated with its interactivity makes it also an ideal educational tool. The software structure and the programming language are detailed. Some examples are provided which illustrate the different steps invoked in the generator operation.     

LQ optimal control for a class of pulse width modulated systems

We consider linear quadratic optimal control for a class of pulse width modulated systems. The problem is motivated from a practical application—digital control of switching power converters. The control synthesis problem is posed based on a sampled data model of the original switching dynamics and a linear quadratic criterion that takes the intersampling behavior into account.     

The mechanical design of a novel Schönflies-motion generator

The design of a novel Schönflies-motion generator (SMG) is the focus of the paper. Schönflies motions are characterized by four degrees of freedom: three independent translations and one rotation about one axis of fixed orientation. The two driving modules of the manipulator are intended to produce, each, two independent motions, pan and tilt. The design philosophy and the layout of the SMG are discussed, along with the design procedure, which includes: (i) part-modelling and visualization, with animation of the device; (ii) evaluation of the main parameters and the characteristics of the different structural realizations, as well as the selection of one single structure meeting best the design specifications; (iii) the design of the main components for the selected variant of the structure; (iv) the structural and modal analyses and determination of the inertial and elastic parameters of the device and its components; and (v) the production of detailed manufacturing drawings. Further results of structural and modal analyses of the SMG are considered, while the link geometry is defined based on the design specifications.