运营商话音质量增强解决方案

泰乐公司的回音消除和话音质量增强（VQE）的VERITY解决方案,能够优化话音清晰度,增强网络性能,从而提高用户满意度。VERITY系列产品可消除声学回音与混合线圈回音,使移动运营商能够在移动到移动、移动到固定的呼叫中,提供有线话音质量水平和无回音服务。对于固定公网运营商来讲,VERITY系统可有效消除混合回音,实现最清晰的话音质量。VQE方案包括泰乐电平控制（TLC）、泰乐声学回音消除（TAC）和泰乐噪音抑制（TNR）。TLC基于每次通话,自动补偿不稳定音频电平;TAC可消除移动网中手机和免提移动终端产生的声学回音…     

基于综合设计“嵌入式系统综合训练”的挑战性学习课程研究

嵌入式系统综合训练的核心内容是让学生自行设计简单的嵌入式系统。综合设计强调对多门课程知识点进行串联和综合应用,因此嵌入式系统综合训练的课题设置应该紧密围绕并力求覆盖嵌入式系统开发的课程知识体系,这样才能做到有的放矢,才能让学生在实际工程中运用理论知识以加深对其直观认识,才不会让综合设计偏离实验教学的主题。因此研究首先对嵌入式系统开发各个环节所运用的课程知识进行分析和梳理,并最终建立嵌入式系统开发课程知识体系。     

光传输系统时延分析

本文主要介绍光传输系统中SDH业务的传输时延的相关知识,以及时延对业务的影响、测试方法、回音及其消除措施等。     

工程理念指导下"信号与系统"教学研究与探索

本文针对"信号与系统"课程里的"信号"以及"系统"的基本原理,将知识构建为一个有机整体.通过在课堂教学中适当引入工程应用案例,并在实践环节设计综合创新实验,初步探讨了工程理念指导下的教学新方法.教学实践表明,该方法对于激发学生学习兴趣、提高学生分析问题、解决问题的能力效果显著.     

在DSK6711板上用BLMS算法实现无线桌面机声学回音抵消的仿真

在很多通信情况下会产生回音，他会严重影响语音的清晰度，一旦回音比较严重时会使得整个系统无法工作，因此需要消除回音。本文要解决的是：当使用无线桌面机通信且按下免提键时，声音会在室内反射然后经过话筒返回而产生回音。现在大部分采用自适应滤波算法来消除回声，多采用LMS算法，由于BLMS算法与LMS算法的效果相同，但BLMS算法的运算量远小于LMS算法，本文采用BLMS算法在DSK6711板上进行了这种回音抵消的仿真。     

电信系统回音问题的产生和控制(上)

电气回波和声学回音是客户投诉语音质量问题的重要部分。随着电信运营商越来越关注客户满意度,如何采用有效方法控制语音服务中的回音成为运营商们普遍关注的一个努力方向。回音控制过程网络损耗(Network Loss)最初的降低(控制)回音技术被称作网络损耗。该技术的原理是通过在传送和接收电路双向设置电阻,增加回音损耗。它的基本目标是通过增加信号/回音比,实现语音信号始终大于回音信号。这种处理技术的明显弱点是,它在衰减回音信号的同时,衰减了有效的语音信号。尽管这种方法简单,而且在短距离和延迟时间短的应用环境中效果不错,但它不可…     

基于DSP的语音采集与回音效果的系统实现

介绍了一种基于DSP芯片TMS320VC5509A并采用TLV320AIC23芯片来采集语音信号以产生回音效果的系统设计方案.同时给出了该回音效果系统的硬件电路和软件流程.     

回声信号处理综合实验设计及实现

针对学生对卷积和相关概念不清的问题,结合生活现象,本文设计了回声信号处理综合实验。实验内容包括回声产生、回声特性分析、回声消除,它将难以理解的卷积、自相关、互相关概念有机地串在一起,帮助学生理解和应用。实践表明,理论推导和实验编程相结合有助于学生将所学的知识融会贯通,且学生在做与生活密切联系的综合实验时,积极性高,收获大。     

化学与化工、石油与冶金工业

0116184提取抽油井液位回音信号中液位值的方法[刊]/孟开元∥测控技术.—2001,20(5),—58～59,62(E)分析了抽油井液位回音曲线的特性,给出了检测曲线中特性脉冲的电路原理,介绍了根据统计规律计算声速和液位值的方法。该方法与计算机结合可以消除在测量中人为读数和干扰的影响,使得测量变得精确、方便、直接。此方法在实际中已得到了较好的应用。参3     

"信号与系统综合设计实验"教学改革与实践

"信号与系统综合设计实验"是本科信号处理系列课程配套的重要实践课程.本文提出了"基于项目的学习和实践"课程设计理念以及在该课程中实施此理念的具体方法和过程.实践证明这些举措对于激发学生的自主学习能力和动手能力、加深知识理解、培养团队合作精神等具有积极的作用,并取得了良好效果.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks