查询词典 analog signal

The holistic design of the system and resolved the designs of software and hardware based on VXI bus are put forward according to the demand of test system. The hardware and software is designed, including the formation and design of hardware system, visual instrument software architecture, program design for instrument driver, high speed real-time data collection. In the dynamic test program, the idea of"software is instrument"was applied to meet the diverse test demands. Last, it is proposed that the VXI test system be developed to more totalization and networked. The basic theory of system identification was introduced briefly at first. The principle of spectrum analysis system identification based on Wiener-Hopf equation was expatiated. and the questions in applying Peusdo Random signal as spectrum analysis methods stimulate signal was studied, The generation principle of the peusdo random signal is researched, the characteristic of peusdo random are analyzed from time domain and frequency domain, the inverse repeat peusdo random signal is brought forward to make up the shortage of ordinary peusdo random signal. And a new chaos genetic algorithmis presented to solve the unprecise problem of the traditional method. In the servo valve dynamic characteristic test system, the spectrum analysis methods was applied successfully, the servo valve dynamic characteristic could be acquired rapidly and exactly, the test results were analyzed and the ameliorate methods were brought forward at last.

结合航天某集团液压测试中心测试系统的需求，提出了基于VXI总线的液压测试系统的整体设计方案，完成了测试系统的硬件设计与软件设计，包括硬件系统构成与设计、虚拟仪器软件结构、仪器驱动程序设计、高速同步实时数据采集等内容；以伺服阀动态特性测试为例设计了测试模块，该模块体现了VXI总线仪器软件开发所倡导的&虚拟仪器&的思想，以软件的灵活应用满足了不同的测试需求；结合自动测试系统的发展，研究了VXI测试系统与网络技术结合，实现各种软硬件资源共享，进一步提高设备及数据的利用率和系统的扩展性，使自动测试向综合化、网络化方向发展；研究了伪随机信号作为谱分析法辨识的激励信号时存在的问题，讨论了伪随机信号的产生机理，从频域和时域分析了伪随机信号的性质及其应用，提出了用逆重复伪随机信号弥补了普通伪随机信号的不足，并以混沌遗传算法对逆重复伪随机信号产生过程中的参数进行优化，可以更合理而不是凭经验产生需要的逆重复伪随机信号。

The experimental results show the validness of the mechanism analyses.2. According to the generation mechanism of the leak acoustic signal, the characteristics of the leak acoustic signal are investigated. The auto correlation technology is adopted to descript the leak signal characteristics due to the ability to analyze the coherence of time series. A new procedure to identify the leak acoustic signal from the disturbed noises is proposed based on the conjunction of correlation and approximate entropy algorithm.3. The principle and application in leak location of the correlation and the adaptive filter techniques are introduced. The problems of the traditional leak location methods are analyzed.4. In order to establish the leak detection signal model, the leak acoustic propagation characteristics are investigated experimentally.

从泄漏声产生机理出发，分析了管道泄漏处湍流拟序结构与空泡间相互作用的机理，认为在该机理作用下，泄漏声信号产生过程具有&不可重复&的特征；由于相关函数具有分析时间序列拟序结构的能力，且近似熵从统计的角度区别时间过程的复杂性，因此，提出将信号相关分析和近似熵理论相结合的方法，提取泄漏声信号&不可重复&的特征，辨识管道泄漏故障发生；在实际检测现场，由于各种管内和管外固定声源噪声(如阀门噪声、工地施工噪声等)常导致泄漏误判和漏点定位错误，重点分析了管内固定噪声源的产生机理和特征，为复杂干扰环境下的泄漏辨识提供理论支持。

The method includes following steps:(1) initial frequency selection;(2) based on modulation mode adopted, the sending end carries out symbol mapping, changes signal spectrum based on label information of sub channel, and sends signal in time domain;(3) based on label information of sub channel, the receiving end carries out equalization for received signal, demodulates signal and accomplishes judgment;(4) carrying out channel estimation or prediction, the receiving end obtains updated information of signal state, and determines whether label information of sub channel is needed to update based on self-adapting judgment rule.

本发明提供了一种移动宽带信道中的自适应选频分块传输方法，该方法包括以下步骤：(1)初始选频；(2)发端根据所采用的调制方式进行符号映射，根据子信道标记信息改变信号频谱，并发送时域信号；(3)收端根据子信道标记信息对接收信号进行均衡，解调信号并完成判决；(4)收端进行信道估计或预测得到更新的信道状态信息，根据自适应判断规则，判断是否需要更新子信道标记信息。

There was significant difference in signal intensity between the cell concentration group and unlabelled cell group during 2 weeks. And significant difference occurred in the 5×105 SPIO-labeled cells per milliliter medium group and unlabelled cell group during 3 weeks.3. In kidneys of ischemia-reperfusion injury,the labeled BMSCs were demonstrated as signal intensity loss in renal medulla on T2*WI sequence in days 1,3,and5.The signal intensity loss was visualized up to 8 days after transplantation,and the signal intensity in the third day was the lowest. Histological analyses showed that most Prussian blue staining-positive cells were well correlated with the area where a signal intensity loss was observed in MRI.

在此细胞浓度的基础上，标记后细胞信号在T2*WI序列的降低在2w后失去统计学意义；而在细胞浓度为5×105/ml时，标记3w后信号在T2*WI序列的降低才失去统计学意义。3缺血再灌注肾损伤家兔细胞移植后第1、3、5天肾脏髓质区信号强度明显下降，至移植后第8天信号改变不明显，其中第3天信号改变最为明显；组织学分析见绝大多数普鲁士蓝染阳性标记细胞分布于肾小管周围，与MRI信号强度下降区域基本一致。

Based advanced controlling strategy now, self-adapting fuzzy PID controller is designed. Simulated with MATLAB/Simulink, system responses tracking step signal, square wave signal, sine signal, triangle signal and saw tooth signal are reproduced.

2结合当前先进的控制策略，针对电液伺服控制径向柱塞变量泵，设计了自适应模糊PID控制器，并通过计算机仿真，再现了系统跟踪阶跃信号、方波信号、正弦波信号、三角波信号、锯齿波信号时的系统响应。

In addition, there are two strands of the head is also black, and are rust, rust can be seen because of lead wire resistance increases, resulting in the signal can not be smooth, telephone through the audio signal, the low band signal can also only phone, there is always the voice of flap, and the use of the ADSL band signal is relatively high, head through the rust on it is very difficult, leading to slow or stop signal transmission.

此外有两处绞合的线头处也发黑了，都是锈，可见正是因为导线生锈导致电阻增大，导致信号不能畅通，电话通过的音频信号，频带低，信号还能通过，只是电话里老是有啪啪的声音，而ADSL的信号使用的频带比较高，线头生锈了就很难通过，导致信号传输变慢或者断流。

Best resolution in the LCD display to show the graphics output of analog signal processing, to convert with the specific address information (the pixels on the screen of the absolute address) of the display signal, and then into the LCD panel, directly to the show signal added to the pixel corresponding to the drive pipe, some with memory addressing and write is similar.

工作在最佳分辨率下的液晶显示器把显卡输出的模拟显示信号通过处理，转换成带具体地址信息（该像素在屏幕上的绝对地址）的显示信号，然后再送入液晶板，直接把显示信号加到相对应的像素上的驱动管上，有些跟内存的寻址和写入相类似。

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。

Then the digital signal is processed in digital field. At last DPTV converts the digital signal into analog signal and display.

数字处理电视是在模拟广播电视传输体制下，将接收到的模拟电视信号转换成数字信号，经过数字处理后再转换为模拟信号并显示输出。

Digital signal processing and analog signal processing is a subset of signal processing.

数字信号处理与模拟信号处理是信号处理的子集。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。