有效数字

Experimental accuracy and repetition of FBG temperature sensitivity and compensation were discussed.have selected several materials which has bigger coefficient of expansion to do packaging components, have made many temperature experiments, there have not flaws, such as aging, crackle, absciss layer, packaging materials have good temperature sensitivity and compatibility with optical fiber;have designed the simple and practical packaging components, have performed a serials of experiments about accuracy and repetition of FBG wave-length, have obtained the first step conclusion;have analyzed the result and made comparison between the result of different experiment, have summarized the best packaging effect and several rules to reduce mistskes.

本文所做的主要工作包括以下几个内容：一、选取了常见的热膨胀系数大的材料制作封装元件，经过多次一80℃到80℃反复测试，封装元件没有出现老化开裂、封装裂纹、空洞、离层等缺陷，封装材料具有良好的温敏稳定性及复用性，与光纤相容性较好；二、对光纤光栅进行简单、实用的封装处理，就封装效果的优劣性、波长测量的准确度、重复性和封装时产生的波长损失等方面进行了一系列的实验，得出了初步的结论；三、对温敏和温度补偿式封装的实验数据进行了详细的分析和对比，从数字上对温变过程中光纤光栅中心波长的改变及温变曲线进行了定量的分析，在大量实验数据分析结果的基础上，总结出哪种材料封装效果更好，以及如何有效的减小实验误差。

In order to evaluate the image scrambling degree effectively,the paper gives difinition of the continuity extent.And a new evaluation method of image scrambling degree based on the number of the continuity extent changes when the positon of the pixel changes is provided.The simulation result shows that the method can measure the impact of the every image scrambling phase.

为了对其进行有效地衡量，给出了图像连续性区域的定义，并根据置乱前后数字图像连续性区域数量随像素点位置的变化而改变这一原理，提出了一种有效的图像置乱程度衡量方法，实验表明，该方法能够清楚地反应图像在各个置乱阶段的置乱效果。

The principles, commonly used methods and criteria of data compression are introduced descriptively.

数字化多媒体信息尤其是数字视频、音频信号的数据量是极其庞大的，给存储、传输以及有效、快速获取信息都带来了严重的障碍，如果不对其进行有效的压缩就难以得到实际应用〔'。

On a calculator, the increase of the least significant digit in the result of a calculation to the next higher number where the subsequent digit in the result is 5 or above.

在计算器中，当计算结果的最低有效位的下一位数字等于或大于5时，最低有效数加1。

The digital high power system based on constant RMS, can adapt to various constant voltage or current application. One application is installed in the air exhauster to control the process of producing the tube of energy-saving lamp.

中文摘要：基于有效值恒定的大功率数字电源系统，具有非常广泛的应用范围，可以适用于各种需要有效值恒定的恒压和恒流电源的场合，如应用在生产节能灯管的排气机——长排车上，用于控制节能灯管的排气过程。

The image watermarking is permuted to reduce the relativity of original pixels, so the error bits of the extracted watermarking are dispersed as well. Therefore the resistance to crop attack is improved significantly.

对数字水印信号进行置乱分散了原始水印信号的相关性，在遭到剪切攻击时可以将错误码元尽可能分散，因此有效地提高了数字水印算法的抗剪切攻击性能。

The image watermarking is permuted to reduce the relativityof original pixels, so the error bits of the extracted watermarkingare dispersed as well. Therefore the resistance to crop attack isimproved significantly.

对数字水印信号进行置乱分散了原始水印信号的相关性，在遭到剪切攻击时可以将错误码元尽可能分散，因此有效地提高了数字水印算法的抗剪切攻击性能。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

Experiments show that the digital trap filter based on window function method of FIR can efficiently reduce the power line interference in SEMG.Furthermore,the frequency around 50 Hz does not be obviously influenced.

实验证明，采用基于窗函数法的FIR原理设计的50 Hz数字陷波器能有效滤除SEMG中的工频干扰并基本不影响50 Hz周围有效SEMG的获取。

Digital RMS detector s principle and character are introduced in this paper,and compare with analogue RMS detector .

介绍了数字真有效值检波器的原理和性能并与其它真有效值检波器做了对比。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。