基于计算机技术的广播电视仿真综合培训平台的设计与实现

为保障广播电视节目的安全播出,对值班人员的日常培训和考核十分重要。针对目前在播出设备上实际操作练习的弊端,本文设计并实现了一种基于计算机技术的广播电视仿真综合培训平台,该平台构建了一整套无线发射台站的仿真系统,通过在计算机上模拟真实设备的操作,达到培训和考核值班人员的目的。     

Inverse Filter of Chaos with Applications on Parameter Estimation

Linear filter may hide simple nonlinearity of chaotic dynamics, which would decrease the accuracy of parameter estimation, and reduce the effect of signal processing. Based on theoretical and experimental analysis, this paper provides a method to recover the dynamics. An example of radar data proves that the dynamics hidden in observed data can be found by inverse filter of chaos. It is also pointed out that inverse filter of chaos can be applied to mine inner regulation of some time series and estimate parameters of nonlinear models in data processing for radar. And the method is significant to clutter modeling.     

C波段TVRO镜像频率抑制微带交指带通滤波器

微带交指带通滤波器具有结构紧凑、易于批量生产的特点，适用于ＴＶＲＯ超外差接收机中作为镜像频率抑制滤波器。本文给出有关设计公式、设计实例。     

A distributed range-free correction vector based localization refinement algorithm

Localization problem is an important and challenging topic in today’s wireless sensor networks. In this paper, a novel localization refinement algorithm for LAEP, which is a range-free localization algorithm by using expected hop progress, has been put forward. The proposed localization refinement algorithm, called as CVLR, is based on position correction vectors and can resolve the LAEP’s hop-distance ambiguity problem, which can lead to adjacent unknown nodes localized at the same or very close positions. CVLR can make full use of the relative position relationship of 1-hop neighboring nodes (called as CVLR1), or 1-hop and 2-hop neighboring nodes (called as CVLR2), to iteratively refine their localization positions. Furthermore, from localization accuracy and energy dissipation perspective, we optimize the communication process of CVLR2 and propose an energy-efficient improved CVLR. Simulation results show that the localization accuracy of CVLR1, CVLR2, and the improved CVLR are obviously higher than that of LAEP and DV-RND.     

基于LabWindows/CVI的电压闪变测量研究

电压闪变是衡量电能质量的一个重要参数,对其进行准确测量具有非常重要的现实意义。虚拟仪器是测量仪器和计算机紧密结合的一种新型的测量仪器。针对此,利用LabWindows/CVI设计了电压闪变测量模块,给出了测量原理、软硬件实现方法及部分关键代码。仿真和应用表明,所开发的电压闪变测量模块性能达到了IEC的闪变仪测量标准。     

利用半导体pn结结电容构成的沟道式电容器

为满足对电子系统中元器件性能提升、面积减小、成本降低等需求,利用感应耦合等离子体刻蚀技术(ICP),对低阻p型硅采用刻蚀、扩散、磁控溅射Al电极等工艺,使之形成凹槽状三维结构,制造出一种特殊的具有高密度电容量的硅基电容器。其特点是结构简单,电容量大(电容密度可达2.2×10–9F/mm2),容值可调,与现有微电子工艺兼容,可用于200MHz至数GHz的退耦或其他场合。同时由于半导体pn结固有的特性,该电容器可取代传统的贴片电容广泛用于电子系统中的退耦、滤波、匹配、静电和电涌防护等场合。     

Leica激光全站仪跟踪测量数据跳变问题的研究

通过大射电望远镜(LT)5m模型,发现测量仪器Leica激光全站仪在动态跟踪测量初期存在3 mm～7mm的数据跳变问题,通过分析找到了问题的来源,提出了解决方案,并通过实验有效的消除了数据的跳变,为以后的实验提供了参考.     

Residual-Based Estimation of Peer and Link Lifetimes in P2P Networks

Existing methods of measuring lifetimes in P2P systems usually rely on the so-called Create-Based Method (CBM), which divides a given observation window into two halves and samples users ldquocreatedrdquo in the first half every Delta time units until they die or the observation period ends. Despite its frequent use, this approach has no rigorous accuracy or overhead analysis in the literature. To shed more light on its performance, we first derive a model for CBM and show that small window size or large Delta may lead to highly inaccurate lifetime distributions. We then show that create-based sampling exhibits an inherent tradeoff between overhead and accuracy, which does not allow any fundamental improvement to the method. Instead, we propose a completely different approach for sampling user dynamics that keeps track of only residual lifetimes of peers and uses a simple renewal-process model to recover the actual lifetimes from the observed residuals. Our analysis indicates that for reasonably large systems, the proposed method can reduce bandwidth consumption by several orders of magnitude compared to prior approaches while simultaneously achieving higher accuracy. We finish the paper by implementing a two-tier Gnutella network crawler equipped with the proposed sampling method and obtain the distribution of ultrapeer lifetimes in a network of 6.4 million users and 60 million links. Our experimental results show that ultrapeer lifetimes are Pareto with shape alpha ap 1.1; however, link lifetimes exhibit much lighter tails with alpha ap 1.8.     

Tunable Photonic Microwave Filter Using a Superstructured FBG With Two Reflection Bands Having Complementary Chirps

A tunable photonic microwave bandpass filter using a superstructured fiber Bragg grating (SFBG) with two reflection bands having complementary chirps is proposed. Being different from a regular chirped FBG, which is usually fabricated using a chirped phase mask with a fixed chirp rate, the SFBG with complementary chirps is fabricated using a uniform phase mask and a chirped sampling function. The chirp rate of the sampling function can be designed to realize specific equivalent chirp rates that are complementary in the 1st-order and the 1st-order reflection bands of the SFBG. An SFBG with complementary chirps is fabricated and characterized. The use of the SFBG to implement a photonic tunable microwave filter with a negative coefficient is experimentally demonstrated.