适用于AFM的数字智能反馈控制器设计

原子力显微镜(AFM)是进行纳米测量和操作的一种重要工具.近年来,纳米科技的迅速发展使得传统AFM越来越无法满足纳米测量快速和高分辨率的测试需求,而反馈控制器的速度是限制AFM成像速度和分辨率的关键因素之一.为此,本文搭建基于高速数字信号处理器(DSP)的数字反馈控制系统,将模糊控制算法与比例积分PI控制算法结合,利用模糊规则自动选择合适的比例和积分参数,改善Z向反馈系统的鲁棒性.基于自制的AFM系统,将该方法与传统PI控制算法进行对比实验,在相同的扫描条件下,该数字智能反馈控制器可在扫描范围为30μm×30μm时,将AFM的行扫描速度由3 Hz提高到40 Hz,验证了该方法能够有效改善AFM的扫描速度和成像分辨率.     

基于DSP的运动控制系统设计

为了满足CNC齿轮测量中心的测量精要求.针时定点数字信号处理器(DSP)TMS320LF2407A的特点,设计一种以DSP运动控制为核心的运动控制系统.该系统通过DSP内部集成的A/D转换模块对传感器电压值进行采样,由DSP控制给出指令,驱动电机运动,实现了位置控制,测量精度大大提高.并给出系统硬件电路设计.根据实际情况,给出CAMAC接口电路设计.     

其它计算机与系统

0119893基于 DSP 的高速数据采集与处理系统[刊]/史晓锋//电子技术应用.—2001,27(6).—78～80(E)提出了一种基于 DSP 的高速数据采集系统的设计方案.对其中高速 A/D、高速缓存、DSP 控制以及数据通讯接口等内容进行了讨论,提出了更为有效的同步控制方式。该设计方案电路简单、可进行多通道扩展、具有一定的通用性。参3     

高速A/D芯片输入信号的调理电路

腔衰荡光谱DSP处理系统中,衰荡信号的数字化需要用高速A/D来实现。目前,高速A/D芯片对输入信号的幅值范围有着严格的要求,为保证输入腔衰荡光谱DSP处理系统中A/D芯片的信号满足其要求,并实现其性能最优化,文章设计了一套以峰值探测器、可变增益放大器、高速运放及C8051单片机为核心器件的高速A/D芯片输入信号调理电路。实验结果表明:该电路满足设计要求,同时,该电路还可用于其它需要对电振幅进行调理的场合。     

基于DSP的线阵CCD数据采集系统设计

DSP系统具有高速、小型化、稳定性好、精度高和集成度高等特点.本文设计了一种基于DSP技术的线阵CCD数据采集系统,以TMS320VC5502型DSP和TLV1572型A/D转换器为例,分析了CCD输出数据和A/D转换数据的工作时序,详细介绍对线阵CCD输出视频信号的数据采集过程,并通过MAX232器件把采集结果传给PC机.该系统设计方案电路简单,可靠性好,易于实现,具有一定的通用性.     

基于DSP的视频采集压缩卡的实现

实现了以TI的TMS320C6205 DSP为核心的高速视频PCI采集压缩卡.该系统采用了PHILIP公司最新推出的视频A/D芯片SAA7114H,将模拟电视信号转换成数字信号,同时CPLD控制将数据流写入FIF0或者中断DSP读出FIFO的数据进行压缩处理.最后将压缩过的数据流再经过PCI总线传入PC机,由PC机完成视频解码.详述了CPLD的控制模块.     

DSP技术在声强测试系统中的应用

根据声强测试过程中对数据处理系统的需求,提出了以数字信号处理器(DSP)TMS320C5409与A/D转换器芯片MAX125为核心构建高速多通道声强数据采集处理系统的方案,并结合它们的特点对该方案进行了论证.同时,详细介绍了TMS320C5409与MAX125之间的硬件接口电路的设计和软件编程的方法.实验表明,该数据采集处理系统具有速度快、可靠性高、结构简单等特点,满足声强测试过程的技术要求.     

基于DSP和高速A/D的电力系统多通道同步采样

介绍了一种以DSP芯片TMS32OC6711D为处理核心,辅以高速A/D芯片ADS8364,实现电力系统多通道同步采样分析的系统结构,着重介绍系统的硬件设计,通过测试及使用表明,该设计使用方便、实时性好、抗干扰性强、测量精度高、性价比优,可在电力系统中广泛使用.     

一种DSP芯片多通道缓冲串行口的配置方法

简单介绍了SPI接口协议的内容和11公司生产的TNS320C5402 DSP芯片,以及如何将该DSP芯片的多通道缓冲串行口McBSP配置为SPI模式(时钟停止模式),从而可以实现DSP芯片与其它处理器(PC机、A/D芯片等)之间的通信,该配置方法广泛应用于高速数据采集系统.     

一种基于DSP＋FPGA的高速数据采集系统设计

结合高速DSP和FPGA各自的特点,设计了一套高速数据采集系统。以浮点DSP为采集系统的核心,对采集到的数据进行滤波及FFT变换等处理。FPGA作为外设,主要对A／D芯片、USB芯片等进行控制。该系统电路结构简单、功耗低、数据传输速度快,可用于电压、电流等模拟量的采集及数字信号的采集。     

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.     

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.     

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.