具有中文语音提示功能的蓝牙数控直流电压源的设计

为了实现电压源的稳定和精准输出,满足"互联网+"时代电源智能化的需求。文中介绍一种具有中文语音提示功能的蓝牙数控直流电压源的设计方案。该系统以STC12C5A60S2单片机为核心,单片机I/O口输出的数字量经过D/A模块、放大模块得到输出直流电压,通过调整单片机的数字量输出,即可改变输出电压值,从而实现数控功能。该电源采用负反馈闭环系统,提高了输出精度。通过加入蓝牙模块和语音播报模块,实现可用蓝牙设备远程调控输出电压值,每次改变输出电压后,会有中文语音提示调整后的电压值。经测试表明,该电源输出精度高,输出响应良好,达到了设计要求     

提供精确互补电压的放大器

图1中的电路生成两个模拟电压,用一种互补方式可以改变这两个电压.当直通输出电压上升时,互补的输出电压下降,反之亦然.两个输出电压之和为恒定值:VOUT+VOUTC=VREF,其中VOUT为直通输出电压.VOUTC为互补输出,而VREF是从带隙单元IC1获得的一个基准电压.     

仿真技术在DX-600合成器中的应用

DX-600发射机合成器工作在高电压、高频率、大电流条件下,检修维护和故障排除都十分困难,采用仿真技术对合成器工作情况进行仿真,通过改变相关元器件的值,分析响应信号波形及输出值的变化,为合成器的检修维护和故障排除提供重要依据。     

双向工作的电源逆变器

如果我们想在负载不均匀的电池正、负输入和输出端之间改变电荷方向,我们就得采用能反相的直流变压器。解决办法之一就是采用图1所示的对称回扫变换电路。该电路能够从一个正电源产生一个负电压输出,或者从一个负电源产生一个正电压输出。在该电路启动的时候,输出端场效应晶体管的衬底二极管,将输出电压提升到同步开关工作开始所需的电压值。如果门控开关信号是对称的,那么输出电压将接近输入电压的95％,而转换效率将大于80％。通     

不同激光二极管能量触发下GaAs 光导开关研究

GaAs 光导开关在较高的场强下可工作于雪崩模式,为此设计了异面体结构的GaAs 光导开关以提高开关场强。 设计的开关芯片厚度为2mm,电极间隙为3mm,利用半导体激光二极管对开关进行了触发实验。当开关充电电压超过 8kV 后,开关输出脉冲幅度显著增强,输出脉冲前沿快于光脉冲,开关开始了雪崩工作模式,且随着开关电场不断增加, 开关输出电压幅值也线性增加。在不同触发能量下,开关输出电压幅值和波形基本没有改变,但在较高的触发能量和高 的偏置电场下,开关抖动较小,实验中开关获得的最小抖动约500ps。     

基于FPGA的三相SPWM变频变压电源的研究

针对传统的变频变压电源采用的模拟控制技术的不足,设计一种基于FPGA的三相SPWM变频变压电源。对主要的硬件电路和基于FPGA的数字控制电路进行研究;分析SPWM波的调频调压原理;通过改变频率控制字来控制开关管生成频率可调的电压,调节调制度和PWM波的占空比来调节输出电压幅值。研究结果表明,系统实现了输出频率和幅值可调的三相正弦交流电,相位彼此相差为120°,输出电压幅值在0～25 V内可调,输出频率在0～100 Hz范围内以0.1 Hz的精度调节。仿真与实验结果证实了该设计方案的准确性和可行性。     

高精密程控电压源设计与实现

提出一种基于MCU的高精密程控电压源实现方法。PC机通过异步串口与MCU通信,远程控制D/A输出,同时使用精密电阻衰减网络压缩电压幅度,提高输出电压精度,输出电压经放大器驱动输出,增强了负载能力。根据大量的测试数据,创造性地拟合输出电压与配置电压值的函数关系,并通过软件修正系统误差和非线性误差,精度可达±1.5μV,完全满足设计要求。     

一种中心值精确可调的高性能带隙基准电压源

不同的集成电路制造工艺,对平衡温度时的带隙基准电压值有影响.为此,本文提出了通过改变带隙基准电压输出级电路结构的方法,实现了在基准电路内部可精确调整基准电压中心值,以满足在不同工艺条件下电路系统对基准电压中心值的精度要求.本芯片根据CSMC公司0.50μm CMOS混合信号工艺模型设计并进行流片.测试结果表明,本文提出的方法能调整基准电压中心值.利用这种方法,可以实现带隙基准电压中心值宽范围的可调,使基准电压的输出完全符合系统所需.     

APFC Boost电路中电压环动态稳定性研究

在APFCBoost电路中,当需要高电压输出时,电压误差放大器易饱和输出致电压环失效,使基准电流幅值达到最大,进而使电感电流无法继续增加,最终输出电压小于设定值。针对该问题,文中提出根据电压环方程式得出的电压环动态稳定性判据来检验设计参数是否能使电压环动态稳定工作,进而使输出电压达到设定值。     

一种新颖的多值基准输出缓冲器设计

对比分析了不同结构的传统多值基准输出缓冲器,提出了一种新颖的多值基准输出缓冲器结构.采用PMOS输出结构提高了输出电压摆幅,利用低输出阻抗结构加快了瞬态响应速度,解决了传统结构无法兼具高输出与快响应的矛盾,电路功耗低、易补偿.基于0.15 μm标准CMOS工艺,用Hspice软件对电路进行仿真.仿真结果表明,当电源电压...     

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.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

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 method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.