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991.
存储媒体的媒体内同步反馈控制算法   总被引:14,自引:1,他引:13  
许延  常义林  刘增基 《电子学报》2002,30(9):1344-1348
本文提出了一种存储媒体的媒体内同步反馈控制算法,该方案是建立在缓冲区占用率控制基础上,通过周期性地检查缓冲区的占用情况来检测失步,并将其反馈给发送方,由发送方对发送帧速率进行调整。文章给出了接收方所需缓冲区的设计准则及发送帧速率的调整方法,并分析了算法中各参数对同步性能的影响。实验表明该方案能够处理由于网络传输时延特性变化引起的失步,与其它反馈控制方案相比具有更低的数据丢弃率,从而使接收端播放平滑连续,具有良好的视频播放质量。  相似文献   
992.
刘文贵 《质谱学报》2002,23(1):38-38
本文重点阐述了本人在探索过程中遇到的疑难问题及解决问题的有效方法:消除电子流对高压系统的影响,负高压的产生和提高荷载能力,磁场反相,离子信号反向和自动控制的改造。  相似文献   
993.
In this paper we present a new reseeding technique for test-per-clock test pattern generation suitable for at-speed testing of circuits with random-pattern resistant faults. Our technique eliminates the need of a ROM for storing the seeds since the reseeding is performed on-the-fly by inverting the logic value of some of the bits of the next state of the Test Pattern Generator (TPG). The proposed reseeding technique is generic and can be applied to TPGs based on both Linear Feedback Shift Registers (LFSRs) and accumulators. An efficient algorithm for selecting reseeding points is also presented, which targets complete fault coverage and allows to well exploiting the trade-off between hardware overhead and test length. Using experimental results we show that the proposed method compares favorably to the other already known techniques with respect to test length and the hardware implementation cost.  相似文献   
994.
在保证网络资源利用率高的条件下如何建立一个使所传图像主观质量最好且有效的MPEG-4传输系统,已成为一个具有挑战性的课题,就此问题提出了一个在因特网上建立MPEG-4视频流的端到端传输方案。  相似文献   
995.
Homogeneous Lyapunov function for homogeneous continuous vector field   总被引:3,自引:0,他引:3  
The goal of this article is to provide a construction of a homogeneous Lyapunov function associated with a system of differential equations , under the hypotheses: (1) vanishes at x = 0 and is homogeneous; (2) the zero solution of this system is locally asymptotically stable. Moreover, the Lyapunov function tends to infinity with x, and belongs to , with as large as wanted. As application to the theory of homogeneous systems, we present two well known results of robustness, in a slightly extended form, and with simpler proofs.  相似文献   
996.
尚庆虎  于美文 《中国激光》1991,18(6):458-461
本文提出了一种利用双相位共轭反射镜的实时图像衬度控制方法。给出了理论分析,提出了一种实验方案,给出了模拟实验结果。  相似文献   
997.
Manufacture of high performance uncooled 1300 nm distributed feed-back (DFB) lasers operating single mode over the −40 to +85°C range requires control of the wavelength variation across a 2″ wafer to less than 10nm and preservation of grating definition during processing and regrowth. We have used atmospheric pressure metalorganic vapor phase epitaxy, without substrate rotation to achieve the necessary uniformity. Material was assessed using photoluminescence, x-ray diffraction, transmission electron microscopy, electrochemical current/voltage profiling, and secondary ion mass spectroscopy. The devices are based on a strained quantum well structure with an n-type grating layer to provide gain coupling. The best result gave a wavelength spread across 32×32 mm center square of a 2″ InP wafer of 3 nm. Buried heterostructure DFBs manufactured with high yield in this way operate from −40 to +85°C, with thresholds at 85°C as low as 18 mA.  相似文献   
998.
带钢热连轧卷取温度控制与改进算法   总被引:6,自引:0,他引:6  
杨卫东  刘杰 《钢铁》1997,32(2):38-42
对带钢热连轧卷取温度控制的主要问题进行了分析,描述了CTC基本控制模型,并在此基础上,提出了两个新算法:全长反馈控制与头部设定自学习,经使用证明这两个新功能具有很好的控制效果。  相似文献   
999.
This paper deals with the problem of global stabilization of linear discrete time systems by means of bounded feedback laws. The main result proved is an analog of one proved for the continuous time case by the authors, and shows that such stabilization is possible if and only if the system is stabilizable with arbitrary controls and the transition matrix has spectral radius less than or equal to one. The proof provides in principle an algorithm for the construction of such feedback laws, which can be implemented either as cascades or as parallel connections (“single hidden layer neural networks”) of simple saturation functions.  相似文献   
1000.
In this second installment of a two part paper that overviews analog feedback circuits, computationally efficient and general feedback analysis techniques applicable to virtually all three and four terminal device technologies are formulated. As developed in Part I, these techniques coalesce signal flow and two port network theories in a way that clearly illuminates the loop gain, driving point I/O impedances, and other characteristics of any type of feedback configuration. More than simply developing the signal flow-two port methodology, this paper demonstrates its design-oriented utility by applying the new technique to the problem of assessing the performance attributes and limitations of four single loop and two dual loop feedback architectures.Three advantages are gleaned by the signal flow-two port method of feedback network analysis. The first advantage is its amenability to a straightforward application of the stability theories and compensation strategies discussed in Part I. The second is its ability to underscore the magnitude of potentially troublesome feedforward factors associated with the feedback network. Once the extent of this parasitic feedforward is highlighted, the topological nature of appropriate feedforward compensation is relatively easy to innovate. The third advantage of signal flow-two port analytical methods is its ability to simplify the analysis of dual loop feedback architectures. This last advantage is noteworthy in view of the fact that dual feedback loops offer the only practical analog mechanism for desensitizing the gain and I/O impedances with respect to uncertainties in open loop parameters.  相似文献   
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