5种环绕声拾音方法空间特性的主观评价实验

为得到不同拾音制式在空间感塑造上的差别,对5种常用的环绕声拾音方法进行主观评价实验,得到各拾音方法在5个空间特性参量上主观心理尺度值,总结出拾音制式中传声器布放对空间特性的影响规律。运用环绕声录音和重放原理,结合对重放声双耳互相关系数测量的数据,对结论进行了分析和讨论。     

谈双声道立体声拾音制式的演化与应用

较详细地阐述了双声道立体声拾音制式的发展与演化,讨论了各种立体声拾音制式的内涵和主要特点,并对这些制式在实际应用当中可能会出现的问题进行了分析。     

INA-5环绕声拾音制式中后方话筒拾取的直达声对前方声像定位的影响（下）

INA－5环绕声拾音制式中后方话筒拾取的直达声对前方声像定位的影响（上） 标题提示： 前言 一 INA－5拾音制式简介 二 INA－5中话筒对L与LS之间的声级差     

XY拾音制式与MS拾音制式的等效转换

从传声器指向性系数的角度入手,简单介绍了XY制式和MS制式的拾音原理,提出了XY制式与MS制式等效转换的一种计算方法,并对其进行了讨论。     

A／B拾音制式

A／B拾音制式的拾音原理 A／B拾音制式是将型号和特性完全一致的两只传声器彼此拉开一定间距构成的立体声传声器系统，在录音时将传声器系统置于声源前方，并将左传声器拾取到的信号馈送到记录载体的左声道：将右传声器拾取到的信号馈送到记录载体的右声道。     

现场拾音中的风噪控制

现场拾音最让人头疼的就是风噪。话筒的拾音原理决定了无法完全消除风噪,只能通过技术手段和拾音技巧降低风噪带来的影响。通过话筒合理摆放等拾音技巧,通过打开话筒高通滤波器开关等音频处理技巧,通过选择好用、合适的防风罩,最大限度地在拾音现场获取干净、高质量的声音。     

立体声拾音仿真软件设计与其数学模型的建立

介绍了自主研发的立体声拾音仿真软件（Virtual Stereo Recording）的功能与编程涉及的数学模型的建立,可完成4种常用立体声拾音制式的仿真,能图示化输出声像位置,参数化显示时间差、强度差等重要参数,而且能将仿真传声器拾取的声音以立体声形式播放,并对4种制式中输出参数的数学模型进行了详细的推导。     

环绕声分离制式双子拾音区域定位研究

以环绕声分离式前方三声道拾音制式为模板,通过计算与数据分析对其两个子定位区域声像还原情况进行考察。证实了在该类拾音方式中,两个子定位区域有效拾音范围的部分重叠导致其声像定位不准确。针对此问题引入Williams的"平滑连接"理论,并确定将以其为主题进行后续的相关研究。     

强度差拾音方式立体声重放声音信号的畸变

近十多年来，立体声技术发展比较迅速，为了利用传声器拾取更加完整真实的立体声信息，许多不同的拾音制式应运而生。应该说，所有这些制式各有优缺点，不存在一种十全十美的制式。     

5.1通道环绕声节目的拾音与制作

立体声录音技术现在已相当成熟，形成了多种拾音制式及制作工艺。建立在立体声基础之上的环绕声节目录制，远没有达到成熟的阶段，在电视、广播及音像制品当中，环绕声节目的拾音与制作至今仍处在摸索与实践之中。本文介绍了一些较为成功的拾音方法，以及环绕声制作的六类表现方法与效果．     

用非线性晶体的相位共轭特性记录扫描全息图

提出一种用非线性晶体的相位共轭特性记录扫描全息图的方法。给出了记录方法的基本原理、记录光路和实验结果     

浅析通俗音乐中人声的录制和处理方法

介绍了录制某类人声所使用的一般传声器和摆放原则,以及后期处理的一般方法和手段.通过获得贵州省新闻出版广电局2014年广播节目录制技术质量奖一等奖作品——《爱在路上》为例,分析和总结了通俗音乐人声录制与处理方法的特点与规律.     

Effects of optical feedback on the light-current characteristics ofsemiconductor lasers

Theoretical and experimental investigations of the continuous wave (CW) output-power current characteristics of semiconductor lasers with optical feedback are reported. An analytical expression is presented which accounts for the external reflection in the form of an effective facet reflectivity. The coherence properties of the compound cavity laser field are incorporated by the correlation function of the optical field. An experimental setup was established to adjust and to control for different feedback levels. The normalized threshold current variation, due to feedback shows a dependence on the laser structure. This results from different confinement factors of the various waveguide structures. Up to reflection levels well within the coherence collapse regime the change of the slope of the light versus current curve is higher than calculated from incoherent feedback     

一种实现Android机顶盒录制节目的设计方法

为使电视节目录制方式适应用户个性化需求,提出一种在Android机顶盒上实现个人视频录制功能的改进方案。对于正在播放的电视节目采用持续录制、定时录制、时移录制三种可供选择的录制方式,根据开始录制的触发条件不同选用不同的录制停止方式;对于未来播放的电视节目采用与电子节目指南信息相结合的预约录制方式,不断更新时间和日期表来实时查询后台监控任务。测试结果表明,该方案有效可行,更好地实现了人机交互功能。     

用Fe:LiNbO_3的实时散斑错位干涉仪

报道一种实时散斑错位干涉仪的实验室装置。采用Fe:LiNbO_3晶体作散斑照相的记录介质。晶体掺Fe量为0.1％摩尔,对λ=488nm波长的透过率<5％。进行散斑照相的同时在Fe:LiNbO_3晶体上形成象全息图。用此装置可以实时地测量物体的形变以及进行实时无损检验。     

双光子吸收光致变色三维光存储实验研究

介绍了双光子吸收光致变色光存储的存储原理，利用单光束双光子吸收三维光存储和反射式荧光共焦扫描读出实验装置，分别进行了写入激光功率、曝光时间和存储深度不同时双光子吸收光致变色三维光信息存储特性(读出信号强度和存储点尺寸)的实验研究。结果表明，读出信号强度主要取决于写入时的激光功率和曝光时间。读出信号强度在激光功率较低时与写入激光功率的平方成正比，而当写入激光功率大于一定值时，读出信号强度达到了饱和。读出信号强度随着曝光时间的增加也明显地呈现出饱和效应。此外，读出信号强度随着存储深度的增加明显地减弱了。存储点尺寸随着写入激光功率的增大、曝光时间的增长也迅速增大。较高的写入激光功率和较短的曝光时间有利于信息的高速存储。     

影响数字全息再现像像质的因素分析

详细地讨论了CCD的感光像元、抽样间隔和感光面积这三个结构参量对数字全息再现像的影响,并分析了结构参量之间的相互关系.结果表明,CCD的三个结构参量不仅分别影响着数字全息图再现像的亮度、大小和分辨率,同时还与记录光路相关联并相互影响.在CCD的结构参量、物体大小及记录波长都确定的情况下,设计了最佳全息记录光路,使CCD的带宽得到了充分利用,获取的信息量也达到了极限.通过综合归纳,给出了充分利用CCD结构参量进行高质量数字全息记录的建议,并进行了实验验证.     

Research on the Shrinking of 2—components Adhesive with Automatically Calculating Hologram

In this paper ,used BSO(Bi12SiO20) crystal as a hologram recording material,TV-camera as a detector ,and a holographic setup controlled by a computer ,automatically calculating hologram of 3- interferograms method is theoretically and experimentally studied. This new holographic recording material and automatically calculating hologram make it possible to use real-time holography in an industry. As a practical example, the shrinking of 2-components adhesive in 4h is measured.     

Error Rates in Generalized Shadowed Fading Channels

Most of the existing models to describe the shadowed fading channels use either the Suzuki or Nakagami-lognormal probability density function (pdf), both based on lognormal shadowing. However, these two density functions do not lead to closed form solutions for the received signal power, making the computations of error rates and outages very cumbersome. A generalized or compound fading model which takes into account both fading and shadowing in wireless systems, is presented here. Starting with the Nakagami model for fading, shadowing is incorporated using a gamma distribution for the average power in the Nakagami fading model. This compound pdf developed here based on a gamma-gamma distribution is analytically simpler than the two pdfs based on lognormal shadowing and is general enough to incorporate most of the fading and shadowing observed in wireless channels. The performance of coherent BPSK is evaluated using this compound fading model.     

Optimization of SIP Session Setup Delay for VoIP in 3G Wireless Networks

Wireless networks beyond 2G aim at supporting real-time applications such as VoIP. Before a user can start a VoIP session, the end-user terminal has to establish the session using signaling protocols such as H.323 and session initiation protocol (SIP) in order to negotiate media parameters. The time interval to perform the session setup is called the session setup time. It can be affected by the quality of the wireless link, measured in terms of frame error rate (FER), which can result in retransmissions of packets lost and can lengthen the session setup time. Therefore, such protocols should have a session setup time optimized against loss. One way to do so is by choosing the appropriate retransmission timer and the underlying protocols. In this paper, we focus on SIP session setup delay and propose optimizing it using an adaptive retransmission timer. We also evaluate SIP session setup performances with various underlying protocols (transport control protocol (TCP), user datagram protocol (UDP), radio link protocols (RLPs)) as a function of the FER. For 19.2 Kbps channel, the SIP session setup time can be up to 6.12s with UDP and 7s with TCP when the FER is up to 10 percent. The use of RLP (1, 2, 3) and RLP (1, 1, 1, 1, 1, 1) puts the session setup time down to 3.4s under UDP and 4s under TCP for the same FER and the same channel bandwidth. We also compare SIP and H.323 performances using an adaptive retransmission timer: SIP outperforms H.323, especially for a FER higher than 2 percent.