双参数logistic映射的同步方法

提出了一种新的通过双参数非线性反馈函数来实现一般logistic映射的驱动响应系统的同步方法，该方法能够避免现有的线性反馈和非线性反馈中出现的弱同步现象，并且在不同的参数空间下同样可以保证同步，对一般的logisdc映射普遍适用。本文重点论述了在2个参数控科下的非线性反馈的同步原理及性能，通过数值仿真验证了该算法的有效性和对噪声的顽健性，并说明了该算法在保密通信中的应用。     

A new approach to the dynamic thermal modelling of semiconductor packages

This paper describes a novel approach to the dynamic thermal characterisation of semiconductor packages. Conceived as an extension of the variable angle model for multilayer structures, the thermal capacitance of each layer is evaluated at the same time and for the same volume used to calculate the thermal resistance, which guarantees the coherence. Because this volume or lump is a function of system geometry, materials and boundary conditions, the model can be said to include 3D aspects. The thermal resistances and capacitances obtained from the model, each pair representing a layer of the structure, are used as input to an electric circuit simulator to obtain the transient response of the package.Moreover, some common assumptions usually made when interpreting the transient thermal response of semiconductor packages are revised and discussed in an attempt to clarify the scene. Particularly, the log-of-time derivative of the step response is shown to give all the information about the dynamic response when the characteristic time constants of the system are widely separated. In that particular case, otherwise very common in practice, a novel analytical method for the obtention of the characteristic time constants and associated amplitudes is presented and their results evaluated for different industrial power packages.     

Virtual phase technology: A new approach to fabrication of large-area CCD's

This article presents a new technology for fabrication of a single-phase CCD. This new technology called virtual phase (VP) employs only a single level gate structure, and is, therefore, ideally suited for fabrication of large-area high-performance devices with high yield, The fundamentals of operation of VP CCD's are discussed, and the advantages and limitations of this new technology are presented. The design, fabrication, and operation of a 490 × 328 TV compatible VP imager is described, and performance parameters as well as imagery are presented.     

A new approach for a phase controlled self-oscillating mixer

The analytical and experimental demonstration of subharmonic synchronization and phase shifting of a push-pull self-oscillating mixer is presented for the first time. Inherent high mixing gain of the self-oscillating mixer circuit is exploited to generate a strong signal at the same frequency of the reference signal, which is related to the local oscillator's (LO) phase information. A phase error between this signal and the reference signal is extracted in a phase comparator before phase locking. Analytical modeling of frequency and phase stabilization of the push-pull self-oscillating mixer is presented, which is also experimentally verified for a self-oscillating mixer at 12 GHz. This self-oscillating mixer circuit demonstrates efficient phase locking, 0°-180° continuous phase shifting capability in addition to the reported large locking range (>10 MHz), low close-in to carrier phase noise (<7 dB degradation of a 6 GHz synthesized reference signal), and a high mixer conversion gain (>17 dB at 17 GHz). The demonstrated subharmonic phase locking approach replaces the need for a frequency multiplier or divider before the phase comparator. The synchronized push-pull self-oscillating mixer circuit is applicable to the millimeter-wave frequency distributed transmitters and receivers, where low-loss phase shifting and efficient subharmonic phase and frequency locking are hard to achieve     

A coordination structure approach to the management of projects

The paper uses object based models to capture and make visible the system level coordination structure of complex projects. These models facilitate the development of a shared view necessary for effective project management. In the paper, development and use of the models are illustrated using examples drawn from the design of custom silicon. We examine three custom silicon design projects to identify the significant coordination problems encountered as well as the difficulties of using activity based project management tools. Then we develop object based models of coordination structure as a tool to overcome these difficulties. We use these models to capture a project manager's view of the four stages of the custom silicon design cycle: design definition, chip design, prototype manufacture, and system integration. We conclude by discussing the relationship between the coordination structure approach and other project management tools, and the managerial advantages of the proposed approach in the management of complex projects. The approach has particular value for the management of projects in which the task structure is complex, uncertain, and unstable, as is typically the case in new product development     

基于单变量信号的混沌同步变结构控制

提出一种基于单变量实现混沌同步的变结构控制方法。该非线性控制策略的有效性通过对Lorenz混沌系统在理论分析和数字仿真两方面得到了证明。     

压控振荡器相位噪声的一种建模研究方法

电感电容压控振荡器（LC-VCO）是无线收发电路中的重要单元,它的频谱纯洁度将直接影响频率合成后的信号频谱,所以相位噪声是VCO的最重要的指标之一。提出了一种研究LC-VCO相位噪声的方法,使用VerilogA语言建立可控噪声和可控寄生电容的晶体管模型,通过用所建立的模型代替原有的spice晶体管模型来构成LC-VCO电路并进行仿真,能够对噪声和寄生电容进行开关控制,从而观察不同的噪声源以及不同的寄生特性对电路相位噪声的影响。使用该晶体管模型,仿真验证了噪声滤波理论中差分对管结电容对最优电感值选取的影响以及滤波电感对白噪声和闪烁噪声不同的抑制作用。     

A new ADPLL architecture dedicated to program clock references synchronization

This paper presents a totally digital phase locked loop (PLL) used for the recovery of a MPEG-2 decoder clock. The All Digital PLL (ADPLL) is implemented with a frequency synthesizer based on a new technique for phase shifting, avoiding the phase accumulation of ADPLL using a ring oscillator or avoiding the multiphase generation if a delay-locked loop (DLL) is used. The strongest point of the proposed configuration is the possibility of implementing as many ADPLLs as needed in a single circuit, in the limit of the circuit resources, without additional external circuit. The transfer characteristic, frequency resolution and jitter performance are computed and discussed. Then, the ADPLL resources and the ADPLL performances in term of time response and jitter are reported.     

一种适用于多相相干解调的载波同步方法

本文介绍了一种新的载波同步方法,并将它用于对载波前导的快速精确同步。文章给出了同步算法的仿真流程和部分仿真结果,并对其应用前景作了简单讨论。     

A new method for phase synchronization and automatic gain controlof linearly modulated signals on frequency-flat fading channels

An optimal phase synchronization and automatic gain control (AGC) scheme for coherent reception of linearly modulated signals on frequency-flat mobile fading channels is presented. The channel model and receiver performance are described. It is shown that using the technique allows the irreducible error floors (due to random FM) known from the noncoherent methods to be practically eliminated. Depending on the fastness of the fading, large power gains over the noncoherent methods are achieved. Unfavorable analog signal processing and/or the high bandwidth inefficiency of the FDM-pilot coherent methods are also avoided     

A new approach to system reliability

Calculating system-reliability via the knowledge of structure function is not new. However, such attempts have had to compromise with the increasing complexity of a system. This paper overcomes this problem through a new representation of the structure function, and demonstrates that the well-known systems considered in the state-of-art follow this new representation. With this new representation, the important reliability calculations, such as Birnbaum reliability-importance, become simple. The Chaudhuri, et al. (1991) bounds which exploit the knowledge of structure function were implemented by our simple and easy-to-use algorithm for some s-coherent structures, viz, s-series, s-parallel, 2-out-of-3:G, bridge structure, and a fire-detector system. The Chaudhuri bounds are superior to the min-max and Barlow-Proschan bounds. This representation is useful in implementing the Chaudhuri bounds. With this representation of the structure function, the computation of important reliability measures such as the Birnbaum structural and reliability importance are easy. The use of Chaudhuri bounds is recommended for general use, especially when cost and/or time are critical. The C-H-A algorithm (in this paper) is simple and easy to use. It depends on the knowledge of the path sets of a given structure. Standard software packages are available to provide the minimal path sets of any s-coherent system. The C-H-A algorithm has been programmed in SAS, S-PLUS, and MATLAB     

A new approach to error-correcting codes

A correspondence between linear(n,k,d)codes and algorithms for computing a systempsiofkbilinear forms is established under which the codelengthnis equal to the multiplicative complexity of the algorithm for computingpsi, and the code distancedis underbounded by the minimum number of multiplications required to compute any linear combination of thekforms inpsi. This hitherto unexplored approach to linear codes holds promise of a better understanding of the structure of existing codes as well as for methods of constructing new codes with prescribed rate and distance.     

A new approach to grating-assisted couplers

A novel approach to the analysis and design of grating-assisted directional couplers is proposed. Power exchange between the waveguides is maximized through phase matching of two power-orthogonal modes of the parallel coupler. It is shown that either complete power transfer or zero crosstalk can be achieved at two different coupling lengths even when the two wavelengths are strongly coupled and/or close to synchronism. An analytical solution to the coupled-mode equations is obtained for the grating of rectangular shape. A grating-assisted coupler made of two slab waveguides is examined as an example to illustrate the salient features of the scheme     

一种长时延网络中移动节点间的时间同步算法

长时延网络的同步对于提升网络传输效率,增加网络吞吐量具有重要意义。现有用于长时延网络典型时间同步协议有TSHL,Tri-Message等,这些同步协议都是针对传播时延保持稳定或者保持短时稳定的长时延网络,但在实际情况中,有时传播时延会发生变化,如节点间相对位移的变化,如何在这样的长时延网络中进行时间同步也是一个值得研究的问题,文中提出了一种运用于长时延网络中移动节点间的时间同步算法,利用节点间多次的信息交互计算出传播时延变化的速率,然后对时延变化进行估算来进行时间偏移的补偿以达到时间同步。     

A dynamic approach to controlling high-level synthesis CAD tools

In this paper, we present a novel model of CAD tool control that can be used in the constraint-directed control of high-level synthesis tools. To enable this control we introduce the concept of a design space reasoning mechanism. We formally describe a statistical based, machine learning process that automatically generates the tool control knowledge necessary to drive the design space reasoning mechanism. The representation of this tool control knowledge in the form of a fuzzy, linear differential, qualitative model is described. Finally, the experimental results obtained using the Magellan system are presented