数显波形发生器的研制

介绍一种由信号发生器专用集成电路MAX038和PIC16C71单片机组成的具有数码频率显示功能的正弦波、方波（脉冲波）、三角波（锯齿波） 信号发生器电路。     

一种简单实用的移相触发线路

简单的RC放电电路形成的锯齿波线性并不佳,若加上电容恒流放电环节,再配以高输入阻抗的比较器作为负载,则可获得良好的线性锯齿波,图1就是一种实用的削顶锯齿波移相触发线路。     

应用于谐振式光学陀螺的正弦波调制解调技术

谐振式光学陀螺(ROG)是一种基于光学Sagnac效应检测转动角速度的高精度惯性传感器。锯齿波和三角波调制会导致谐振信号出现大量毛刺噪声以及复位脉冲的问题,通过正弦波调制解调可以解决上述问题,而且具有更高调制频率的优势。搭建了光学微谐振腔调制解调实验系统,分析了正弦波调制参数的变化对谐振曲线与鉴频曲线的影响。在调制频率为4 MHz,调制幅值为2 V时,得到了最为平滑的谐振曲线与最佳线性度的鉴频曲线。为光学微谐振腔在谐振式陀螺系统应用中相位调制选择最佳的参数提供了参考。     

简易低频信号发生器的设计

介绍了采用89C52单片机设计产生正弦波、三角波、锯齿波、方波4种信号的低频信号发生器的方法,阐述了系统硬件电路的设计要点和软件的实现过程。实验表明：低频信号发生器产生的各种波形频率和幅度在一定范围内可调,且稳定性好。设计的电路和操作方法适用于一般的简单信号发生器的系统设计,硬件设计也有一定的应用性和普及型,对开发功能全面的信号发生器具有积极的指导作用。     

正弦波非线性平滑变频方法的实现

提出了一种基于DDS（直接数字频率合成）技术的正弦信号发生器波形平滑变频的设计与实现方案，阐述了正弦信号发生器的硬件电路、系统程序总体设计和非线性平滑变频方法的实现。该方法解决了正弦波形在非线性变化频率过程中造成的叠加和脉冲跳变等问题，提高了正弦波形变频中两波形的衔接平滑度。实验和实测结果表明，该方法的硬件电路简单、程序设计灵活巧妙、波形衔接平滑度好、可靠性高，具有较高的实用价值。     

基于LabVIEW的虚拟信号发生器的设计研究

详细介绍了虚拟仪器的概念、优点及其系统组成,同时介绍了现在比较流行的图形化编程语言LabVIEW,并用该语言开发设计一虚拟仪器——信号发生器,以此来说明虚拟仪器的开发方法和步骤等.该虚拟信号发生器不但界面友好,而且功能强大、操作简便.经仿真实验表明,它能够产生实验室常用的正弦波、三角波、方波、锯齿波等波形,频率范围较宽,具有相关参数可调功能.     

多功能波形发生器

本文介绍一种模拟式多功能波形发生器。它由斜波发生器和脉冲及阶跃电压发生器两部分组成,可以产生初扫方向和终扫方向任意可变,起始、上限、下限和终止四个电位独立连续可调的单程斜波、锯齿波及各种复杂的三角波。进行中的斜波可随时保持在某一电位也可随时改变扫描方向。该发生器还能输出占空比可调的单脉冲、连续脉冲、单阶跃、双阶跃和三阶跃电压波形。     

用SIMULINK实现脉宽/脉频调制中的占空比控制

提出一种在利用Matlab仿真软件中的Simulink模块进行仿真时，通过一个可控频率的三角波发生器与反馈量的比较，实现脉宽或脉频调制中的占空比控制的方法，并进行了相应的理论分析与仿真研究。结果表明，该方法大幅度简化了脉宽或脉频调制波发生器的结构。提高了仿真的效率．     

利用PC机集中控制MARX发生器充电电源设备

给出PC机集中控制MARX发生器充电电源设备系统的硬件构成，PC机与各MARX发生器充电电源设备之间的通讯原理和通讯协议，系统的软件实现，说明系统抗干扰解决办法。     

新超低频任意信号发生器

以单片机为核心,设计了一个超低频任意函数信号发生器.该信号发生器采用数字波形合成技术,通过硬件电路和软件程序相结合,可输出自定义波形,如正弦波、三角波、方波和锯齿波及其他任意波形,且超低频的功能突出.详细介绍了任意波形的生成原理、硬件电路设计以及软件系统部分的设计原理.波形的频率和幅值在一定范围内可任意改变.与传统信号发生器只有固定的几种输出波形相比,具有输出波形的任意化和低频精度高的特点.     

Computer Recording in Rapid Scan ESR Spectroscopy

SUMMARY

Rapid scanning [1, 2] in ESR spectroscopy is one of the methods by which one can obtain significant information relating to rapid chemical reactions occurring in several milliseconds. One of the advantages of this rapid scanning method is the ability to investigate phenomena occurring rapidly and singly, such as a decay of electrons trapped in a solid matrix. This note reports on the coupling of an electronic computer (JEOL JEC-5) with the rapid scan unit in order to record ESR spectra with high signal-to-noise ratio in several milli-seconds, and also on the successful application of this technique to the study of chemical reactions. This use of the computer is neither as a computer of average transients (CAT) [3, 5] nor as a sampling method for the detection and display of rapidly changing spectra [6, 7]. The apparatus used in this experiment consists of an ESR spectrometer, a Helmholtz coil, a power amplifier, a sawtooth wave generator, a trigger pulse generator, and an electronic computer. A block diagram of the equipment is shown in Fig. 1. Although details of the rapid scan method and the units other than the computer were described in a previous paper [2], several parts have been improved as follows. The dimensions of the Helmholtz coil were changed to 10.2 cm outer diameter and 6.5 cm inner diameter, and the unit was made of 10 turns of 0.7-mm copper wire. By feeding the sawtooth current to the coil after amplification by a solid-state SEPP OTL power amplifier a more linear field sweep was obtained than previously.? The trigger pulse, the repetition rate of which ranges from 200 msec to 10 sec, initiates simultaneously both the sawtooth wave generator and the computer. The purpose of using the computer is to store the ESR spectra observed by the rapid scan method during a rapid chemical reaction and to display these spectra on the chart of a conventional recorder after complete termination of the reaction. About 100 μsec are required for analog-to-digital conversion in the computer used. Sixteen ESR spectra, each of which was ob served for 20 msec, were stored in the computer during a chemical reaction. For this operation a program was compiled so as to store 192 sampling points for each spectrum; the number of these sampling points was sufficient to get a precise and smooth curve for each spectrum displayed. The application of the technique was demonstrated for an experiment on the decay reaction of the electrons trapped in 2-methyltetrahydrofuran, MTHF.     

基于Verilog HDL的DDS任意波形发生器设计

简单介绍了直接数字频率合成技术（DDS）,利用DDS设计任意波形发生器,其能够产生矩形波、正弦波、三角波、锯齿波等多种波形;采用Verilog HDL语言实现了各个模块功能。并在QuartusⅡ6．0开发环境下进行仿真。下载至cyclone Ⅱ系列FPGA芯片得到验证。     

发电机运行状态对定转子径向振动特性的影响分析

分析隐极同步发电机定转子径向振动随发电机运行状态的变化规律。首先通过分析不同运行状态时发电机电磁关系、电枢反应特性,以及正常运行时作用于定子的脉振电磁力特性和作用于转子的不平衡电磁力特性,分别得到定子径向倍频振动和转子径向工频振动在励磁电流一定时随发电机有功功率的变化特征,以及有功功率一定时随励磁电流的变化特征。实测了SDF-9型隐极同步发电机定转子振动信号,与理论分析结果基本吻合。另一方面也揭示基于振动特征诊断发电机故障时,必须考虑发电机的运行参数和运行状态,否则其诊断结果在实际应用中是不完整的。     

串联式混合动力车恒流发电控制方法的研究

对一辆串联式混合动力中巴车的辅助动力单元充电策略进行了研究,在动力系统简化模型的基础上,分析了辅助动力控制单元电流控制的工作原理.为提高其混合动力模式时对蓄电池充电的效率,提出了辅助动力单元恒流发电控制方法.在ADVISOR2002原控制策略模块的基础上,建立该控制算法模型,并进行了整车仿真.仿真结果表明,当采用65A恒流发电时,充电时间及燃油消耗均比恒温器控制策略有明显的下降,能够满足实际需要,为下一步实车实验奠定了基础.     

三波谐波齿轮传动圆盘式波发生器的设计

建立了用于三波谐波齿轮传动的圆盘式波发生器分析模型，根据弹性理论得到波发生器作用下柔轮的径向位移与切向位移表达式，进而求出柔轮的弯曲应力计算公式，通过分析不同包角情况下柔轮弯曲应力沿圆周方向的分布，确定柔轮弯曲应力幅值最小时的角色，从而确定波发生器的圆盘半径以及圆盘的偏心距。给出了传动比为68的设计实例和设计过程。     

转子绕组短路故障下不平衡电磁力计算方法

通过建立发电机有限元分析模型,得到故障下发电机内部磁力线走势、发电机气隙磁通密度的变化以及短路位置、短路匝数和励磁电流对转子不平衡电磁力的影响。对工程实际中常用的等效磁通法和磁势叠加法进行了分析比较,同时改进了现有的等效磁通计算方法。将两种方法不平衡电磁力的计算结果与有限元方法结果进行比较,指出了结果存在差异的原因。     

基于数值模拟的造波机设计与实现方法研究

以摇板造波方式为例,推导了造波方程和消波方程,建立了造波板运动特性与波浪参数的对应关系。设计了垂向板造波模型和摇板造波模型,利用Fluent软件进行了波浪数值模拟,使用UDF控制造波板运动,在近壁面附加动量源消波,对比分析了两种造波方式的优劣。垂向板造波方式适用于小幅波,对动力源要求低;摇板造波方式适用于中幅波,波浪质量好。依据数值模拟数据,设计并研制了物理样机,开展了波高测量实验。基于数值模拟的造波机设计方法能够快速确定造波方式和关键技术参数,大大缩短了研制周期,降低了研制成本,对研制新型造波机具有重要的借鉴意义。     

基于VHDL语言的数字波形发生器的设计

阐述了数字波形发生器系统的设计方案,给出了系统的原理框图,并对设计功能进行了描述;详细介绍了系统主要功能模块的作用和工作原理,并对部分模块在MAX＋PLUSIIIO．2中进行了仿真;仿真结果表明,系统能够产生正弦波、方波、三角波和锯齿波,产生的4种波的频率、幅值可以调节,还可以通过4位数码管显示输出波形的频率。     

Improvement of machining characteristics of micro-EDM using transistor type isopulse generator and servo feed control

This paper describes the improvement of machining characteristics of micro electrical discharge machining (micro-EDM) using a newly developed transistor type isopulse generator and servo feed control. The RC generator is mainly applied in conventional micro-EDM even though the transistor type isopulse generator is generally more effective for obtaining higher removal rate, because the transistor type generator is unable to generate iso-duration discharge current pulses with small pulse duration (several dozen nano-seconds), which is the normal level for micro-EDM. A new transistor type isopulse generator was therefore developed using a current sensor with high frequency response. With the new transistor type isopulse generator developed, the pulse duration can be reduced to about 30 ns, which is equivalent to the pulse duration used in finishing by the conventional RC pulse generator for micro-EDM. In order to achieve stable machining and improve machining characteristics, a new servo feed control system for micro-EDM using average ignition delay time to monitor the gap distance was also developed. By integrating the transistor type isopulse generator with this new servo feed control system, we were able to obtain a removal rate of about 24 times higher than that of the conventional RC pulse generator with a constant feed rate in both semifinishing and finishing. The effectiveness of the servo feed control proved higher in finishing than in semifinishing, whereas the transistor type isopulse generator was more effective in semifinishing than in finishing.