共查询到20条相似文献,搜索用时 62 毫秒
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介绍了一种短Turbo码交织器的设计方法 ,给出了一个短交织器的设计例子 ,其仿真结果表明 ,这种交织器对于短Turbo码很有效。在Turbo码帧长度处于 10 0到 10 0 0时 ,与Turbo码使用块交织和伪随机交织相比 ,误码性能有了大幅度的提高。 相似文献
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无线光通信差错控制系统的时问参数特性 总被引:2,自引:0,他引:2
在无线光通信系统中,光强闪烁和大气衰减等因素将使通信系统产生长突发误码,结合Turbo码,建议并分析了两种差错控制方案中时间参数的特性。对于Turbo码 信道交织的差错控制方案,仿真分析了不同信道交织深度下的无线光通信系统性能,给出了特性曲线。对于Turbo码 反馈重发(ARQ)的方案,仿真结果表明反馈环路延迟时间的变化不影响系统的平均吞吐量,但是将影响平均数据传输延迟和重发次数的概率分布。 相似文献
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该文提出了一种针对高误码条件下Turbo码交织器的恢复方法,应用于码率为1/3的并行级联Turbo码。信道编码识别是非合作信号处理领域的重要内容,Turbo码交织器的恢复是其中的一个难点。现有的识别方法可以有效地处理无误码时的问题,而实际通信中Turbo码经常应用于信道质量较差的情况,此时误码率会较高,且码长较长,这些方法将失效。利用校验向量的特征,可将交织器的每个位置分离开来,单独求解,使得交织器中每个位置的恢复仅依赖于几个相关的位置,避免了误码累加效应,从而解决了在高误码率,长码长时的识别问题,其复杂度较低。在仿真结果中,对典型的长度达10000的随机交织器,接收序列10%误码率的情况下,实现了正确的恢复。 相似文献
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删余Turbo码的交织删余的综合设计研究 总被引:1,自引:0,他引:1
删余(Puncturing)是构造高码率Turbo码的主要方法。介绍了删截Turbo码的原理,研究了交织和删余相结合的综合设计删余Turbo码的思想,基于这种思想,设计了一种新颖的交织删余结合的删余Turbo码的设计方案,并给出了实现算法。仿真表明,该综合设计获得了更为优越的性能特性。 相似文献
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Turbo编译码器中交织器的选择 总被引:2,自引:0,他引:2
本文探讨了Turbo编译码器中交织器的选择问题。首先从Turbo码的并行级联编码方案和基于最大后验概率(MAP)算法的迭代译码原理出发分析了交织器对Turbo码的纠错性能的巨大影响,然后总结了Turbo码中交织器设计的一些基本方法并分析其各自特点,最后给出了Turbo码中有关交织器的实用性结论。 相似文献
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Michael Reilly 《半导体技术》2004,29(12)
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
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Thomas M.Trexler 《半导体技术》2004,29(5)
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
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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
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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
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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
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Qi-jiang Ran Pei-de Han Yu-jun Quan Li-peng Gao Fan-ping Zeng Chun-hua Zhao 《光电子快报》2008,4(4):239-242
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
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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. 相似文献
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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
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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. 相似文献
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《中国通信》2014,(7)
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