查询词典 analog to digital converter

In this paper, the concept of network security and security structures of OSI and Internet is introduced, and various threats confronting the computer network are also discussed. Several kinds of network information security technologies, including firewall technology, virtual private network, intrusion detection system, data encryption technology, identity authentication and security protocol etc. are also examined. The security of internal network is the biggest problem in the construction of each network. The solution to this problem lies in setting up a firewall. The theory of a firewall and the approach to its actualization is studied. Intrusion detection system, an important part of the computer network security system, has gained extensive attention. IDS monitors the computer and network traffic for intrusion and suspicious activities. It not only detects the intrusion from the extranet hacker, but also the intranet users. The emergence of virtual private network paves the way for realizing secure connection of LAN quickly and at a relatively low cost. The concept, function, key techniques, including the tunnel technology, and the ways to realize VPN are expounded in this paper. Also introduced is the data encrypt network technology, which is called the soul of computer network security, such as digital digest, digital signature, digital certificate, digital encrypt arithmetic and so on. At the same time, the principle and the process of implementing network security by digital certificate and digital signature, the basic principle and characters of security protocols, and finally, three of the security protocols, concerning the security problems in network, IPsec, SLL and SET are analyzed in detail Computer network system should be a system of dynamic defence, both dynamic and static, passive as well as active, and even offensive, combined with management and technology.

本文系统地介绍了网络安全的概念、OSI及Internet的安全体系结构，并讨论了计算机网络面临的各种安全威胁；内部网络的安全问题是每个建网单位面临的最大问题，可以认为防火墙技术是解决网络安全的一个主要手段，本文研究了防火墙的原理及其实现手段；作为一种主动的防御措施，入侵检测系统作为网络系统安全的重要组成部分，得到了广泛的重视，TDS对计算机和网络资源上的恶意使用行为进行识别和响应，不仅检测来自外部的入侵行为，也监督内部用户的未授权活动；虚拟专用网技术的出现，为实现网络间的连接提供了快速安全但又相对便宜的手段，本文较深入的探讨了实现VPN的隧道技术，并对VPN的概念、功能、实现途径、基本构成、关键技术及发展前景等问题进行了全面论述；数据加密技术是网络安全核心技术之一，本文从数据加密算法、数字摘要、数字签名及数字证书等几方面简要介绍了数据加密技术，并分析用数字证书和数字签名实现网络安全的原理和过程；对安全协议的基本原理、主要特点进行了较为深入的研究，并就网络的安全性问题剖析了三种安全协议：IPsec协议、SLL协议和SET协议。

In this dissertation, digital lock-in detection techniques under integer period sampling and non-integer period sampling are separately investigated (1) Under integer period sampling, digital signal sequence is acquired through sampling the measured signal, but digital reference sequence is acquired through mathematical operation, then digital lock-in detection can be realized by calculating crosscorrelation function of digital signal sequence and digital reference sequence Harmonic measure is also analyzed, and a method of measuring harmonic of a periodic signal under aliasing is put forward.

本文对使用采样ADC把模拟信号转换为数字信号并通过计算数字信号的相关函数来实现锁定检测的技术进行了研究，在此基础上设计了一个多功能的数字LIA并在一些科学实验中进行了应用。本文对整周期采样和非整周期采样时的数字锁定检测技术分别进行了研究。(1)在整周期采样时，对被测信号进行采样得到信号序列，而参考序列由数学运算得到，通过计算信号序列和参考序列的互相关函数就可实现锁定检测。

For preparing for the researches of text digital watermarking and advantaging other researchers" development when using the Chinese mathematical expression theory, this paper designs and realizes a development platform of Chinese mathematical expression. It has been proved by experiments that the platform"s function, execution speed and stability can satisfy the requirements of conversion and operation of enormous data.This research found out that the structure information of Chinese have plenty redundant information that can be used by the Chinese mathematical expression for the digital watermarking, the data embedded can possess better robustness. Based on this finding, this paper designs a kind of text digital watermarking method of embedding watermarking by using Chinese structure, and realizes the method by using the Chinese mathematical expression platform.Considering the watermarking embedding algorithms importance to the robustness of the text digital watermarking, this paper makes fully use of the advantage of the Chinese mathematical expression theory to design a kind of layered text method, which has being realized by using the Chinese mathematical expression platform. The layered text method can handle the text as a solid structure, and the embedding data havepreferable robustness.Finally, based on the researches of the text digital watermarking method and the text layered method, this paper integrates the method of making use of the Chinese structure embedding watermarking with the robust algorithm based on text layered, and realizes a brand-new text digital watermarking method. Proved by lots of experiments, this brand-new method has good robustness and better invisibility.

为了为研究工作做准备和方便其他使用汉字数学表达式理论体系的人进行开发，本文基于汉字数学表达式理论设计实现了一个汉字数学表达式平台，实现了Unicode汉字集中的汉字、汉字数学表达式、汉字的Unicode码之间的相互转化、依据汉字数学表达式提取汉字的结构信息、由汉字数学表达式在非中文平台上不依赖字库显示汉字的图像等功能，使用复合文档技术和流压缩技术进行数据的存储，使用对汉字数学表达式进行二叉树拆分来处理汉字数学表达式中包含的信息，使用自定义哈希函数来提高运行速度，实验证明，该平台功能、速度和稳定性完全能满足大量数据的转化和运算要求；通过研究表明汉字的结构信息中存在大量可使用汉字数学表达式理论加以利用的水印加载空间，加载在该空间的数据可以具有较好的鲁棒性，基于此，本文设计了一种利用汉字结构加载水印的文本数字水印方法，并使用汉字数学表达式平台将其实现；由于水印嵌入算法对于文本数字水印的鲁棒性至关重要，本文充分利用汉字数学表达式理论的优点，设计了一种文本分层的方法，并使用汉字数学表达式平台将其实现，使文本成为一个立体的空间，使嵌入在其中的数据具有更好的鲁棒性；最后在基于汉字数学表达式的文本数字水印嵌入方法的研究和基于汉字数学表达式的文本分层方法的研究的基础上，结合利用汉字结构嵌入水印的方法和基于文本分层的抗攻击文本水印嵌入算法实现了一种全新的文本数字水印方法，经实验证明，该方法有良好的鲁棒性和较好的隐蔽性。

This dissertation introduces the whole scheme、the hardware electro circuit design and software design, the result of experiment on salinometer is preferred at the end of the dissertation. Salinometer is base on SOPC technology, and use digital technology to design circuit: the excitation source for balance bridge is generated by digital method, its shape、amplitude and frequency can be control by digital signal, the standard branch of bridge is composed of three digital-analog-conversion, and uses the method of successive approximation to regulate the balance of bridge.

盐度计以SOPC技术为基础，通过数字化方式设计测量电路：电桥的激励源由数字化方式产生，激励源的波形、幅值和频率等可由数字量控制；平衡电桥标准支路由3个数模转换器组合实现，测量时以逐次逼近的方式调整电桥的平衡度；检测电桥平衡度的高灵敏度数字检流计同样以数字化方式设计，它的增益由程序控制，将电桥的输出电压数字化，以软件判断电桥平衡度。

Shandong journey from the journey from Canton Electronics are electronics factory in Jinan in Shandong to set up offices, is responsible for "PCER journey from" Series Products in Shandong Province and other channels of distribution and after-sales service, Canton journey from an electronics factory (line forming the Department of cable) is a professional manufacturer of VGA lines / HDMI Digital Line / DVI digital line / USB Line / Parallel Port Print Line / 1394 digital line / KVM and three lines / MP3 Line / MP4 Line / power cord / AV Audio Video Cable / PS2 mouse keyboard line / network and other computer peripherals jumper cable; 2 are specialized in the production line RVV jacket / RVVP shield / 75-3 75-5 SYV Coaxial / 3 +4 3 +6 five core RGB coaxial lines and other projects large-screen security monitor cable; are specializing in the production of three VGA divider / VGA switch / VGA video devices extended / KVM Switch / KVM Extender / PC to TV (VGA signal transduction AV signal) converter / DVI digital signal splitter / DVI Switch / HDMI Splitter / HDMI switches and other products.

山东征途者电子是广州征途者电子厂在山东济南成立的办事处，主要负责&PCER征途者&系列产品在山东省的渠道分销及售后服务等，广州征途者电子厂一部是专业生产VGA线/HDMI数字线/DVI数字线/USB线/并口打印线/1394数码线/KVM三并线/MP3线/MP4线/电源线/AV音视频线/PS2鼠标键盘线/网络跳线等电脑周边连接线；二部是专业生产RVV护套线/RVVP屏蔽线/75-3 75-5 SYV同轴线/3+4 3+6 五芯同轴RGB大屏幕线等工程安防监控线缆；三部是专业生产VGA分频器/VGA切换器/VGA影音延长器/KVM切换器/KVM延长器/PC转TV转换器/DVI数字信号分配器/DVI切换器/HDMI分配器/HDMI切换器等产品。

Application of the scene in the past, with PLC analog output signal sent to an analog input digital instrumentation display of the occasion, can now use digital realization.

现场应用中，过去用PLC模拟量输出信号送模拟输入数字仪表显示的场合，现在可以用数字量实现。

It is therefore sensible to separate analog and digital circuitry to prevent digital noise from corrupting analog performance.

为了不影响模拟电路的性能，应该把模拟电路的电源和数字电路的电源隔离开。

The inventer controller composed by separated analog devices before has developed into analog-digital or full digital controller based on microprocessor.

逆变控制器的发展经历从分立元件的模拟电路到以专用微处理芯片为核心的电路系统，并从数模混合电路过渡到纯数字控制的历程。

, [Chapter 5 of analog-digital conversion and digital-analog conversion], Chapt...

[第4章单片机功能应用]，[第5章模数转换与数模转换]，[第7章人机接口技术]，[第8章通信接口技术]。

Analog and digital grounds should be tied at one common ground point to minimize circulating digital and analog ground currents and noise.

模拟和数字地应该连接到公共的地上的一点，以使流过的数字地和模拟地电流和噪声尽可能的小。

Although translator has turned from being a crystal ball by which the original culture can unrestrainedly penetrate to another crystal ball by which the target culture can freely traverse, the translator's personal embodiment, in the process of cognitive act, are still absent in translation studies. Translators are still subjects without body or simply disembodied subjects.

译者虽然由原语文化可以自由穿透的玻璃球变成了译语文化可以自由穿越的玻璃球，但译者认知过程中的个体体验在翻译研究中依然缺席，译者依然仅仅是一个没有躯体体验的主体。

Chillingly, he claimed our technology is 'not nearly as sophisticated' as theirs and "had they been hostile", he warned 'we would be been gone by now'.

令人毛骨悚然的，他声称我们的技术是'并不那么复杂，像他们一样，和"如果他们敌意"，他警告说，'我们将现在已经过去了。