基于Windows平台的音效增强系统设计与实现

针对消费电子类产品中扬声器体积小型化所导致的低频重放能力有限、动态范围较小、频响曲线不佳、声场过窄等问题,开发了iSurround音效增强算法,包括扬声器均衡、图示均衡器、立体声增强、虚拟低音、动态范围压缩和自动音量控制等.在Windows平台上以虚拟声卡的形式实现该算法,最后运用主观听音实验的方法,证明了iSurround音效增强算法在低音表现力、声场宽度、空间环绕感等方面有明显提高.同时,也与目前主流音效算法就行了比较.     

小型扬声器感知低音的生成算法优化

虚拟低音技术针对扬声器低频重放问题提供了一种较好的处理方式,其建立在“虚拟音高”理论基础上,将扬声器输入信号在不能重放的低频部分利用其高次谐波成分在听感上虚拟出基频音高.考虑到小型扬声器频带窄、失真大等特性,在虚拟低音的相位声码器算法基础上,用二阶求导的方式对频谱低频峰值进行取点,对不同频段生成不同的谐波个数,简化幅度控制,提出适合于小型扬声器的低音谐波生成模块优化算法并实现.主观实验结果表明改进后的算法在增强低音效果的同时也能保证较好的整体音质效果.     

音箱和功放如何出好低音(下)

三、音箱的摆位和调整 音响系统的音源从留声机发展到CD、DVD等数字媒体,但最终发声的扬声器的原理一直没有太大的变化.重放低音的扬声器一定有很大的开口.新的音响系统追求低音的重放,都希望选用超低音箱.但是重放低音所需的超低音箱和号角时常要受到一些物理的限制,从古至今,亘古不变.听音室内声音的传播,音箱的摆位的基本原理也是不变的.在音响系统的规模受到一定限制,要想获得优质的低音重放,根据音响的基本要义,对音箱的摆位进行精细的调整,就是一件非常重要的事了.     

音箱和功放如何出好低音（下）

三、音箱的摆位和调整 音响系统的音源从留声机发展到CD、DVD等数字媒体，但最终发声的扬声器的原理一直没有太大的变化。重放低音的扬声器一定有很大的开口。新的音响系统追求低音的重放，都希望选用超低音箱。但是重放低音所需的超低音箱和号角时常要受到一些物理的限制，从古至今，亘古不变。听音室内声音的传播，音箱的摆位的基本原理也是不变的。在音响系统的规模受到一定限制。要想获得优质的低音重放，根据音响的基本要义，对音箱的摆位进行精细的调整．就是一件非常重要的事了。     

正反相位音响系统

正反相位音响系统即正反相位传输放大扬声系统。其主要特点是让立体声电信号左右一路正相位和一路反相位传输放大的音响系统。正反抵消可以减弱立体声低频放大电路公共端线上的信号，减小功放电源的电流电压波动，改善信号传输放大质量；可以方便的配接单只单音圈超低音扬声器音箱，节省功放与扬声器系统，适用于各类立体声音响系统设计、制造、改进与配置。具有成本低，品质高，用途多，简便易行，音质效果改善明显等特点。     

Alpine的Bass Engine Ready超低音扬声器

Alpine最新的BassEngineReady超低音扬声器是首次由美国人设计和管理的,有TypeR和TypeS两种款式。此超低音扬声器具有极耐用的结构和独特的装饰性设计,使它们能产生极佳的低音,且动态范围宽阔。安装在新型的BassEngine技术的超低音扬声器,能极好的重放来自该公司的BassEngineEquipped前部装置（headunits）和BassengineReadyV12放大器的强有力的低频输出。TypeS型超低音扬声器具有Alpine的独特的大振幅设计,它具有Kevlar增强型振盆,大振幅的Santoprene悬边和定制的高强度的模压盆架。定制的双重的特大型Nomex定心支片,可提…     

打造小型有源立体声扬声器系统(二)

二、有源超低音音箱 大家知道,要使音箱发出深沉而强劲的低音,就需要利用大振膜扬声器在箱体里进行大幅度的低频振动,使音箱能够排出和吸人大量空气,而要做到这一点,就需要使用大口径扬声器、大容积箱体和大功率低频放大器。本刊上期介绍的小型立体声有源音箱虽然音质不错,但所用低音扬声器的口径只有13cm,箱体容积仅约4升,其100Hz以下的低频响应并不理想,需要用一只单独的超低音音箱来弥补本扬声器系统的低频响应。下面介绍的小型超低音有源音箱就是为此而专门设计的。     

超低音音箱的计算机辅助设计

在设计家庭影院系统时,不少人往往将大部分注意力放在影视显示器材方面,而对音响系统则考虑较少。很多年来,扬声器一直是音响系统中最薄弱的环节,特别是超低音一般都受到严重的衰减。音响系统如果缺少了超低音,影片中原有的雷鸣电闪般的临场真实气氛就会丧失。特别是在观看动作片时,缺少     

Bose推出RoomMatch RMS218超低音模块扬声器

Bose RoomMatch 阵列模块扬声器系列新增一名新成员——RoomMatch RMS218超低音模块扬声器。RoomMatch RMS218超低音模块扬声器专为采用Bose RoomMatch渐变指向性阵列且低频下潜需求低至25Hz的扩声系统所设计,使用场合包括演艺中心、舞厅、礼堂、教堂等。     

低音及低音音箱

专家将人耳可听范围20Hz—20kHz的频率分成七段。其中,20Hz—160Hz横跨三个八度,属于低频段。我们常说的大鼓、大提琴、巴松管、管风琴、钢琴等都可发出浑厚的低音。有人说:聆听低音有一种气沉丹田的感觉,是一种享受。 然而,要通过扬声器重放低音就难了,尤其是要重现极低频和低频段(20Hz—80Hz)的超低音就难了。音响界至今仍在为之奋斗。     

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.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

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.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

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.