查询词典 analog to digital

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。

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。

Analog to Digital Converter is the interface of analog and digital circuit, its use is very extensive.

模数转换器是模拟电路和数字电路的接口，其用途非常广泛。

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。

An analog-to-digital converter, as an interface between analog signal and digital signal, especially is demanded in video and wireless communication field.

高性能模数转换器作为模拟信号与数字信号的桥梁，尤其在图形、视频以及无线通讯等领域的需求日益增强。

Analog music is converted to a digital signal via an analog-to-digital converter.

模拟音乐通过模拟数字转换器转换为数字信号。

In order to change the electric signal to optical signal and recover to electric signal, the system circuit includes analog-to-digital converter, serializer/deserializer, and digital-to-analog converter and level translators.

在保证稳定传输一路视频信号、一路串口信号和四路正反向控制数据信号的基础上，组建了主站和单站间局域网，实现了单站和主站间的数据高速共享与转储。

The relationships of signal-to-noise ratio of sampled signal, analog filter before analog-to-digital converter and sampling rate have been discussed, the results of the discussion have instructiveness for the design of digital receivers.

该文讨论采样后信噪比与模数转换器前的模拟滤波器以及采样率之间的关系，所得结论对数字接收系统设计有指导意义。

Article 144 The Government of the Hong Kong Special Administrative Region shall maintain the policy previously practised in Hong Kong in respect of subventions for non-governmental organizations in fields such as education, medicine and health, culture, art, recreation, sports, social welfare and social

第一百四十四条香港特别行政区政府保持原在香港实行的对教育、医疗卫生、文化、艺术、康乐、体育、社会福利、社会工作等方面的民间团体机构的资助政策。原在香港各资助机构任职的人员均可根据原有制度继续受聘。

Small wonder, then, that the Chinese spend more in the shop than any other group of foreign visitors do .

这样的小惊喜，使中国顾客比任何国家的人消费得更多。