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1.
介绍了人造卫星用70.5kHz和94.5kHz差接桥型压电陶瓷滤波器的设计原理和试验结果。该滤波器的主要特点是通带宽且平坦、波动小、插损低和性能优良  相似文献   

2.
计敏 《电讯技术》1994,34(5):26-29
本文介绍了125kHz小型棒状曲振机械滤波器的设计及实际达到的性能。此种机械滤波器体积小,重量轻,在同类性能的滤波器中具有显著的优点。  相似文献   

3.
白德钊  洪志良 《微电子学》1997,27(4):247-250
介绍了转折频率为35Hz的超低通开关电容滤波器单元的设计。滤波器的时钟频率为8kHz,最大电容比为51,单位电容为0.2pF,采用3μmCMOS SMDP工艺实现。该电路对小信号有较好的信噪比。  相似文献   

4.
本文利用集总参数等效电路模型计算了声表面波波导耦合双模谐振窄带滤波器的频率响应。讨论了谐振器各设计参量对滤波器性能的影响。在X-112°YLiTaO_3基片上实验制作了中心频率114MHz左右,Δf_(-3dB)分别为70kHz和40kHz的二极和四极窄带滤波器。对二极滤波器,阻带抑制小于一30dB;对四极滤波器,阻带抑制小于一50dB;匹配后插损3dB。理论计算与实验结果一致。  相似文献   

5.
介绍了一种用2μmN阱双层多晶硅CMOS工艺实现的音频低通MOSFET-C连续时间滤波器,该滤波器实现了带内波动为0.1dB,通带截止频率3.4kHz的传输函数特性。设计了一个具有精确输出平衡电平控制的平衡结构差分运算放大器,以实现该滤波器的平衡网络结构,对芯片的测试结果进行了分析讨论。  相似文献   

6.
利用集总参数等效电路模型计算了声表面波双模耦合谐振滤波器的频响.通过改变谐振器各个参量使滤波器指标满足要求.在ST石英基片上成功研制出中心频率228MHz,△f-3dB=150kHz,插损为3dB,阻带抑制小于-50dB的铁路专用寻呼机用滤波器。理论计算与实验结果一致。  相似文献   

7.
HP新型合成式信号发生器系列产品介绍盛薇HP新型合成式信号发生器系列产品包括:HP8647A(250kHz-1GHz)、HP8643A(100kHz-1GHz)、HP864SB(100kHz-2GHz)、HP8G48C(10kHz-3.2GHz)。该...  相似文献   

8.
单片机实现的超声频SPWM逆变器的研究   总被引:1,自引:0,他引:1  
文章介绍了一种适合于超声换能器的SPWM(正弦脉宽调制)逆变器。本系统控制电路采用最新单片机技术与正弦脉宽调制技术相结合,功率开关管采用速度极高的VDMOS器件,从而实现了逆变调制频率为180kHz~270kHz,输出正弦波频率为20kHz~30kHz满足了负载换能器的要求。同时也突破了国内报道的调制频率几十千赫,输出正弦波频率几千赫的现有水平  相似文献   

9.
首先对设计方案和基本原理进行了分析,接着对该系统的核心逻辑设计进行了详细说明,探讨了大功率发射机工作在长波(15kHz-40kHz)时,如何利用现场可编程门阵列(FPGA)来对发射机回路的调谐元件进行控制的逻辑设计的方法,实现了在15kHz-40kHz之间频率调谐与控制、单片机和PC机之间串口通信。  相似文献   

10.
DA1000-20比特数字音频解码器马云数字音响的重放性能首先取决于数字音频解码器,DA1000是高性能的数字音频解码器,它可以自动适应32kHz、44.1kHz和48kHz三种取样频率的数字信号,音频输出具有20比特分辨率,110dB的动态范围,1...  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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  相似文献   

20.
正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first  相似文献   

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