查询词典 digital signals

a kind of design project of multifunction electric power quality gauged instrument based on virtual instrument is put forward in this article.this system integrates virtual instrument programming and power electronics together,to realize diverse signals of current electric power quality field allin one.the integrated signal generator unit which carries out the collection of high speed digital data,d/ a conversion and analog output in four channels,unsymmetrical synchro control fifo etc.by fpga are introduced,the flow of electric power system various signal which generates by vc programming is elaborated,and the structural design of signal amplification unit is analysed.the experiment text result shows that this gauged instrument has attained current advanced high grade of accuracy and it will accelerate the steps of electric power quality calibration because of its accuracy and versatility.

摘 要：提出一种基于虚拟仪器技术的多功能电能质量标定仪的设计方案，采用虚拟仪器编程技术和电力电子技术相结合实现集目前电能质量领域的多样信号于一体。介绍采用fpga实现高速数字量采集、d/a转换及4通道模拟量输出、非对称同步控制fifo等的集成信号发生单元，阐述利用vc编程实现的电力系统多样信号的产生流程，分析信号放大单元的结构设计。实验测试结果表明该标定仪达到目前先进的高精度等级，由于其准确性和多功能性将加快电能质量标定的步伐。

A dynamic monitoring and identifying system of Fe2O3 series gas sensors for the research of electronic nose is introduced. The system has 6 channels to input 0~2.5V voltage signals, measures system temperature, makes thermoregulation for sensor with hardware and has LCD screen and voice function. The heating circuit using TL494 chip and PWM mode is realized. Offline and online identification is realized. The hardware design is based on 16 bits MSP430F149 microcontroller. The software design for digital acquisition and identification based on Windows operating system is compiled by Visual Basic 6.0. The test results show that friendly interface, simple operation, accurate data, reliability and stability are obtained. The real-time monitoring for all of the sensors in aerometry or identification can be realized by BP ANN.

介绍了一种用于电子鼻研究的Fe2O3系列气敏传感器阵列动态测试、控制和识别系统；该系统能够同时采集6路0~2.5V的模拟电压信号，测量系统温度、硬件对传感器进行温度补偿，同时具有液晶显示和语音功能；加热电路用TL494芯片采用PWM方式实现，能实现脱机和联机两种不同的识别模式；以16位单片机MSP430F149为核心设计了硬件系统，用Visual Basic 6.0设计了基于Windows操作系统下的数据采集与模式识别软件；该软件界面友好，操作简单，数据结果准确，运行可靠、稳定，既可以长时间实时显示各传感器的全部动态响应过程，又可以用BP神经网络进行模式识别。

Digital sets can display analog TV signals, but not always very well.

数码电视也能显示模拟电视信号，但效果不是很好。

With the progress of science and technology, TV is changed from analog signals TV to digital TV.

随着科技的进步，电视正在由传统的模拟信号电视向数字电视过渡。

With the advancement of fiber optics, lesser time is required to convert analog signals to digital format.

与提高光纤，较少需要一段时间，才能转换成模拟信号以数字格式。

This system mainly contains the front-end pulse interception and back-end software analysis. In the first part, we used a non-invasive infrared measurement method based on the dual channel simultaneous measurement technique. We measured the photo-plethysmograph from the subject's fingers and toes simultaneously, then used an analog circuit and central control unit to process the signals. Finally, the digital volume pulse data is processed by a personal computer. Because the characteristic points of digital volume pulse always occur in sharp variations, this paper proposes two algorithms to solve this problem. First, we find the pacemaker and percussion wave peak from transient slope variation, and then locate the dicrotic notch and dicrotic wave peak by using the wavelet transformation algorithm. When we analyze the data, we use the Visual Basic graphical user interface, which together with the Matlab is the core of the system.

本系统主要包含前端脉波撷取及后端软体分析两部分，其中前端脉波撷取部份是以非侵入式的红外线量测方式，双通道同步量测受测者手指与脚趾的光容积变化描记图，同时将此讯号经类比处理电路及中央控制单元输出成为数位容积波，再传送至个人电脑中；而在后端软体分析部份，因数位容积波之特徵点皆出现於波形中急剧变化的部份，故本论文以瞬间斜率变化量来定位脉波讯号中的起搏点及主波峰顶点，并利用小波转换演算法（wavelet transformation algorithm）来分析重搏切迹与重搏波顶点；程式撰写主要以Matlab为核心，结合Visual Basic的图形化使用者操作介面，增加系统与使用者间的亲和力。

The process of clasp samples deflected by loading and returned by unloading was tested and electric signals were collected by an omnipotent material machine. The analogous electric signal was converted to digital signal by digital converter and stored in a computer. The elastic limit and the relevant enclasp force were analyzed using a relative software.

应用万能材料试验机测试采集试件加载变形及其卸载回复全过程的电信号，通过A/D转换器将电信号转换成数字信号并贮存于计算机中；应用基于MATLAB平台开发的计算机绘图软件处理分析、计算锻丝卡环弹性极限及其相应卡抱力。

XDSL is an end-to-end digital technology like ISDN, so there is no converting and reconverting signals between digital and analog.

XDSL是像ISDN，一样的端到端数字技术因此不需要在数字与模拟方式之间来回转换信号。

Furthermore, an integrative anti- interference solutions are provided, which are consisted of both hardware ones and software ones. Solutions in hardware include a multi-layer shielding structure and proper groundings of the whole system. Solutions in software include digital data pretreatment based on wavelet, FIR digital filter and algorithm of improved high order sine fit method. They do resolve the corresponding problems in on-site monitoring caused by strong electromagnetic field, noise in signals and harmonic and the fluctuation of power system frequency.

同时建立了以屏蔽结构和接地措施为主体的硬件抗干扰和以小波变换预处理、FIR数字滤波器、改进的tg δ高阶正弦拟合算法为主体的软件抗干扰相结合的综合抗干扰措施，有效解决了现场强电磁场干扰、信号中噪声干扰、谐波干扰以及系统频率波动等问题。

Furthermore, an integrative anti- interference solutions are provided, which are consisted of both hardware ones and software ones. Solutions in hardware include a multi-layer shielding structure and proper groundings o f the whole system. Solutions in software include digital data pretreatment based on wavelet, FIR digital filter and algorithm of improved high order sine fit method. They do resolve the corresponding problems in on-site monitoring caused by strong electromagnetic field, noise in signals and harmonic and the fluctuation of power system frequency.

同时建立了以屏蔽结构和接地措施为主体的硬件抗干扰和以小波变换预处理、FIR数字滤波器、改进的tg δ高阶正弦拟合算法为主体的软件抗干扰相结合的综合抗干扰措施，有效解决了现场强电磁场干扰、信号中噪声干扰、谐波干扰以及系统频率波动等问题。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。