基于ISP芯片的可编程周期信号测试仪的设计

介绍了应用ISP芯片实现数字系统的方法，并以周期信号测试仪的设计为例，说明了基于可编程逻辑器件的数字系统设计的特点。     

以色列不允许ISP利用VoIP传输国际电话

以色列通信部已经要求Internet服务提供商（ISP）保证它们的系统不被用于传输VolP国际电话,以免旁路以色列政府授权经营国际电话服务运营商的服务。     

Multistage amplifier topologies with nested Gm-Ccompensation

This paper presents a multistage amplifier for low-voltage applications (<2 V). The amplifier consists of simple (noncascode) low gain stages and is stabilized using a nested transconductance-capacitance compensation (NGCC) scheme. The resulting topology is similar to the well known nested Miller compensation (NMC) multistage amplifier, except that the proposed topology contains extra G _m feedforward stages which are used to enhance the amplifier performance. The NGCC simplifies the transfer function of the proposed multistage amplifier which, in turn, simplifies its stability conditions. A comparison between the NGCC and NMC shows that the NGCC has wider bandwidth and is easier to stabilize. A four-stage NGCC amplifier has been fabricated using a 2-μm CMOS process and is tested using a ±1.0 V power supply. A dc gain of 100 dB has been measured. A gain bandwidth product of 1 MHz with 58° of phase margin and power of 1.4 mW can be achieved. The op amp occupies an active area of 0.22 mm². Step response shows that the op amp is stable     

Novel topologies for DC-DC converter with PWM control

Two topologies for the buck converter are presented. The first converter consists of two active switches whereas the second converter, derived from the parent twoswitch converter, consists of only one active switch. The main feature of this new converter is the ability to operate at a constant switching frequency using a simple PWM control. The design of the gate circuit is simplified as there is only one switch. The converter has a good efficiency, as is proved by the experimental results. The operation of the parent two-switch converter, from which the new single-switch converter is derived, is also presented to gain insight into the design of the new converter.     

基于ISP1161的USB摄像头嵌入式Linux设备驱动

介绍一种在嵌入式Linux环境下实现USB摄像头驱动的方法,它采用具有USB Host协议的接口芯片ISP1161,通过分析Linux设备驱动原理以及ISP1161和USB摄像头芯片组工作机制,实现了USB摄像头的嵌入式Linux设备驱动,并在基于IntelXscale PXA255的Sitsang平台上实现了基于USB等时传输模式的图像数据采集.     

一种支持ISP的Flash在嵌入式设计中的应用

在基于VxWorks的嵌入式系统开发过程中,设计和调试板卡支持包BSP(Board Support Package)是一个较复杂的问题.在对比常用的bootrom实现的方法后,提出一种支持在系统编程(ISP)的Flash在嵌入式中的应用实现方法,并对该方法的硬件电路设计和器件编程进行较详细说明.该设计方法的引入降低了BSP开发难度,提高开发效率.     

基于ISP的VPN网络--NetShuttle带给你灵活自如的VPN解决方案

随着社会经济的发展和技术的进步,企业也日益扩张,客户分布日益广泛,合作伙伴日益增多,在促使企业效益日益增长的同时,也越来越凸现传统虚拟专用网的功能缺陷。尤其是传统虚拟专用网基于固定物理地点的组网方式已难以适应现代企业的需求。 ISP提供的VPN是一种网络服务,它通过网络运营商提供虚拟专用网络     

Resonant converter topologies with three and four energy storageelements

Generalized half-bridge and full-bridge resonant converter topologies with two, three and four energy storage elements are presented. All possible circuit topologies for such converters under voltage/current driven and voltage/current sinks are discussed. Many of these topologies have not been investigated in open literature. Based on their circuit element connections and source and load excitation types, these topologies are classified into resonant and nonresonant topologies and on their physical realizability. Comparison based on exact steady state analysis are given for typical second- and third-order series resonant converters whereas the fourth-order topology is based on the approximate analysis     

Magamp postregulators for symmetrical topologies with emphasis onhalf-bridge configuration

The authors point out the major differences between symmetrical topology magamps and the forward converter magamp. In a forward converter, a small portion of the magnetizing current of the power transformer is diverted to the secondary for reset of the magamp's saturable reactor. In symmetrical topologies, the transformer's magnetizing current is not used for reset of the saturable reactor(s). The magnetizing current shifts to the secondary where it causes a series of problems. The authors examine these problems, identify solutions, and explain why a half-bridge magamp supply is inherently less versatile than is the forward converter     

FDCCII-based FDNR simulator topologies

In this article, three new circuits for realising frequency-dependent negative resistance (FDNR) are proposed. All proposed circuits employ a single fully differential current conveyor, grounded capacitors and resistor. Proposed circuits consist of minimum number of passive and active elements. All proposed circuits are lossless FDNR. The performance of the proposed FDNR is demonstrated on the third-order Butterworth low-pass filter. Simulation results are included to verify the theory.     

一种支持ISP的Flash在嵌入式设计中的应用

在基于VxWorks的嵌入式系统开发过程中,设计和调试板卡支持包BSP(Board Support Package)是一个较复杂的问题。在对比常用的bootrom实现的方法后,提出一种支持在系统编程(ISP)的Flash在嵌入式中的应用实现方法,并对该方法的硬件电路设计和器件编程进行较详细说明。该设计方法的引入降低了BSP开发难度,提高开发效率。     

具有ISP功能的单片机AT89S8252

介绍了美国ATMEL公司推出的具有ISP功能的单片机AT89S8252的主要特点和应用要点。     

Comparison of high impedance input topologies with low EMI susceptibility

Different Input Topologies with resistance to electromagnetic interferences (EMI) are analyzed and compared in terms of EMI reduction. The emphasis in this study is put on circuit robustness and applicability to industrial applications, which requires sufficient EMI rejection over all process corners. Furthermore, a new topology based on a replica amplifier is introduced, that is more robust to process variation compared to previous works (Jean-Michel Redouté and Michiel Steyaert, ESSCIRC, Sept. 2008; Fiori, IEEE Transac Electromag Compat 49(4):834–839, 2007) that rely on accurate matching of absolute values in order to achieve efficient EMI cancellation.     

Reliability of local area networks with bus and ring topologies

The reliability of local area networks with bus and ring topologies with a simple transfer medium are critically analysed. A double transfer medium is used to increase reliability. The efficiencies of these approaches are compared.     

Generating realistic ISP-level network topologies

Simulations are an important tool in network research. As the selected topology often influences the outcome of the simulation, realistic topologies are needed to produce realistic simulation results. Using several similarity metrics to compare artificially generated topologies with real world topologies this paper gives hints on how to use the widespread topology generators BRITE, TIERS, and GT-ITM to create realistic topologies.     

Multicell converters: derived topologies

Multicell converters were introduced ten years ago and, over this period, their properties have been thoroughly analyzed. Since then, this concept has lead to some other innovative topologies which are briefly presented in this paper. Different ways to introduce soft switching in multicell converters are investigated. The concept of distributing power over several switches, giving more degrees of freedom and using less passive components, is extended further with the stacked multicell topology. Finally, direct AC-AC converters using the multicell approach are described.     

Current buffer compensation topologies for LDOs with improved transient performance

The goal of internal frequency compensation of a low dropout voltage regulator (LDO) is the selection of a small-value, ESR-independent output capacitor. Cascode compensation formed by a common-gate transistor acting as a current buffer, an optional series resistor, and a compensation capacitor creates a dominant pole and a left-half-plane (LHP) zero, allowing adequate phase margin and stable LDO design. To this end, a 1.21?V output, 100?mA, 0.1?C10???F output capacitor, ESR-independent, low voltage LDO using cascode compensation with replica bias is designed and fabricated in a 0.5???m CMOS process with an area of 0.22?mm². A line regulation of 0.05% V/V, load regulation of 0.001% V/mA and dropout voltage of 220?mV were measured. LDO-specific pole-zero analysis is detailed. In addition to this design, two improved transient response LDO architectures using cascode compensation with split-length transistors are also explored. A Power Good feature is discussed, which enables direct interface between the LDO and a micro-processor.     

BGP routing policies in ISP networks

The Internet has quickly evolved into a vast global network owned and operated by thousands of different administrative entities. During this time, it became apparent that vanilla shortest path routing would be insufficient to handle the myriad operational, economic, and political factors involved in routing. ISPs began to modify routing configurations to support routing policies - goals held by the router's owner that controlled which routes were chosen and which routes were propagated to neighbors. BGP, originally a simple path vector protocol, was incrementally modified over time with a number of mechanisms to support policies, adding substantially to the complexity. Much of the mystery in BGP comes not only from the protocol complexity, but also from a lack of understanding of the underlying policies and the problems ISPs face that are addressed by these policies. In this article we shed light on goals operators have and their resulting routing policies, why BGP evolved the way it did, and how common policies are implemented using BGP. We also discuss recent and current work in the field that aims to address problems that arise in applying and supporting routing policies.     

Virtual topologies for multicasting with multiple originators in WDM networks

In this paper, we consider the problem of multicasting with multiple originators in WDM optical networks. In this problem, we are given a set S of source nodes and a set D of destination nodes in a network. All source nodes are capable of providing data to any destination node. Our objective is to find a virtual topology in the WDM network which satisfies given constraints on available resources and is optimal with respect to minimizing the maximum hop distance. Although the corresponding decision problem is NP-complete in general, we give polynomial time algorithms for the cases of unidirectional paths and rings.     

Efficient lookup on unstructured topologies

We present LMS, a protocol for efficient lookup on unstructured networks. Our protocol uses a virtual namespace without imposing specific topologies. It is more efficient than existing lookup protocols for unstructured networks, and thus is an attractive alternative for applications in which the topology cannot be structured as a Distributed Hash Table (DHT). We present analytic bounds for the worst-case performance of LMS. Through detailed simulations (with up to 100,000 nodes), we show that the actual performance on realistic topologies is significantly better. We also show in both simulations and a complete implementation (which includes over five hundred nodes) that our protocol is inherently robust against multiple node failures and can adapt its replication strategy to optimize searches according to a specific heuristic. Moreover, the simulation demonstrates the resilience of LMS to high node turnover rates, and that it can easily adapt to orders of magnitude changes in network size. The overhead incurred by LMS is small, and its performance approaches that of DHTs on networks of similar size