Inernet音频技术概述

Internet音频产业 随着Internet的普及,Internet也迅速成为一个音乐发行渠道.消费者可以从Internet上把他们最喜欢的歌曲或新近发行的歌曲下载到便携式播放器中.     

Esoteric SA-60 SACD/CD/DVD-Audio播放机

Esoteric是日本著名的音响品牌TEAC（第一音响）旗下的副牌品牌，它定位在高级音响器材范畴内。一般来讲，这个品牌是以数年磨一剑的速度来推出产品的，一旦推出新品，其必屹立江湖、傲视群雄。     

An introduction to chaos

Chaos, apparently disordered behaviour which is nonetheless deterministic, is a universal phenomenon which occurs in many systems in all areas of science. For it to take place, the equations describing the situation must be nonlinear and, therefore, they are rarely solvable in closed form. Since the advent of fast digital computers, the theory of nonlinear systems has become much more accessible to study and is now undergoing rapid development. The authors review some of the universal aspects of chaos and its ramifications in the field of electronics     

An introduction to CTBI

CTBI provides a simple mechanism that bonds multiple levels of multiple lanes (electrical and optical) in a single step through 66-bit block striping with low overhead and no need lo backpressure or flow control the MAC layer, and allows for a very simple optical module even if the number of optical lanes and electrical lanes are not equal (in / n).     

An introduction to Web Services

This paper provides an introduction to Web Services. A brief history of Web Services is given, leading into an overview of the key Web Services technologies. The paper describes the way in which the IT industry has embraced Web Services and the uses to which the technologies are currently being applied. It concludes with a view of the role of both the key developers and standards bodies in the creation of Web Services and discusses the ways in which this process needs to be supported in order for Web Services to evolve. This revised version was published online in July 2006 with corrections to the Cover Date.     

An introduction to contemporary cryptology

An appraisal is given of the current status, both technical and nontechnical, of cryptologic research. The principal concepts of both secret-key and public-key cryptography are described. C.E. Shanon's theory of secrecy (1949) and G.J. Simon's theory authenticity (1984) are reviewed for the insight that they give into practical cryptographic systems. Public-key concepts are illustrated through consideration of the Diffie-Hellman public-key-distribution system and the Rivest-Shamir-Adleman public-key cryptosystem. The subtleties of cryptographic protocols are shown through consideration of some such specific protocols     

An introduction to Cu electromigration

Electromigration is a major reliability concern in today’s integrated circuits due to the aggressive scaling of interconnect dimensions and the ever-increasing current densities at operation. In addition, the recent introduction of new materials and processing schemes lead to even more challenges in guaranteeing interconnect robustness against electromigration failure. In this article, we review basic electromigration physics in which the main differences between Al- and Cu-based interconnects relevant to electromigration are covered. We also discuss recent process-related advances in electromigration reliability such as the use of alloys and metal caps. Next, the impact of low-k inter-level dielectrics (ILD) on electromigration performance is addressed. Finally, the methodology of electromigration lifetime extrapolation, including reliability assessments of more complex interconnect geometries, is covered.     

An introduction to factor graphs

Graphical models such as factor graphs allow a unified approach to a number of key topics in coding and signal processing such as the iterative decoding of turbo codes, LDPC codes and similar codes, joint decoding, equalization, parameter estimation, hidden-Markov models, Kalman filtering, and recursive least squares. Graphical models can represent complex real-world systems, and such representations help to derive practical detection/estimation algorithms in a wide area of applications. Most known signal processing techniques -including gradient methods, Kalman filtering, and particle methods -can be used as components of such algorithms. Other than most of the previous literature, we have used Forney-style factor graphs, which support hierarchical modeling and are compatible with standard block diagrams.     

An introduction to frequency standards

Quartz oscillators and rubidium, cesium, and hydrogen atomic frequency standards are described in terms of the physics of operation. Sources of frequency instability and inaccuracy are given. The author's intention is to provide a basis for characterization of the more practical aspects of commercially available frequency standards, and to present a comparison of such standards which may be useful in selecting devices for various applications. Emphasis is laid on stability performance of precision frequency standards, but some discussion is also given of other physical characteristics and cost considerations     

An introduction to IC testing

IC testing has evolved from the patterns established some years ago in the production of semiconductors. Since manual testing cannot meet the complex needs indigenous to IC manufacture, highly sophisticated instruments and test systems have developed that are automatically programmed by computer, tape, or printed-circuit card. This article focuses on many of the problems encountered and techniques employed, and also the requirements imposed on automatic IC testing systems.     

An introduction to policy management

Policy management is an all-encompassing term that describes how the QoS policies applied to a network would be managed. This paper illustrates the complexity of policy management, and goes on to explain how the end result of installing a new network policy only happens after a range of both business and network rules are followed. Business rules check that the requested policy is permitted under the customer’s agreed service package and other non-network variables such as the time of day, while network rules include access control functions that check the network has sufficient free capacity before admitting the new policy. Various examples illustrate the importance of co-ordinating policies across the network and that the most appropriate policy is installed in the first place. Poor policy management may result in a next generation network appearing to offer a worse quality of service than the completely best-effort network it is replacing.     

An introduction to voice search

Voice search is the technology underlying many spoken dialog systems (SDSs) that provide users with the information they request with a spoken query. The information normally exists in a large database, and the query has to be compared with a field in the database to obtain the relevant information. The contents of the field, such as business or product names, are often unstructured text. This article categorized spoken dialog technology into form filling, call routing, and voice search, and reviewed the voice search technology. The categorization was made from the technological perspective. It is important to note that a single SDS may apply the technology from multiple categories. Robustness is the central issue in voice search. The technology in acoustic modeling aims at improved robustness to environment noise, different channel conditions, and speaker variance; the pronunciation research addresses the problem of unseen word pronunciation and pronunciation variance; the language model research focuses on linguistic variance; the studies in search give rise to improved robustness to linguistic variance and ASR errors; the dialog management research enables graceful recovery from confusions and understanding errors; and the learning in the feedback loop speeds up system tuning for more robust performance. While tremendous achievements have been accomplished in the past decade on voice search, large challenges remain. Many voice search dialog systems have automation rates around or below 50% in field trials.     

An introduction to synthetic-aperture radar

One way of achieving fine-resolution terrain imagery using airborne, side-looking radar is to boost frequency; another is to decrease along-track tracking. Neither is attractive. But they would have had to do were it not for coherent wave radar?upon which synthetic-aperture radar is premised. Using coherent radar, resolution can depend, not on the width of the beam, but on Doppler frequency shift. The azimuthal resolution of side-looking radar can therefore be of the same order of magnitude as that for range resolution. The key to converting the theoretical groundwork into a ``full-bodied' system is an appropriate data-processing scheme. And the simplest scheme for working, processing, and deciphering the data is optical.     

An introduction to TSAPI and network telephony

Discusses the integration of the telephone into the desktop work environment. This objective can be achieved in a number of different ways. The approach described uses the client-server model. Network telephony is a service that provides the capability to establish, answer, route, and terminate telephone calls under the control of applications on either desktop computers or servers resident in the network. It is accessed by applications via a standard programming interface (telephony services application programming interface, TSAPI) and utilizes a centralized server-based interface with the private branch exchange (PBX) to access the switching and telephone control services that the PBX provides. Creating a logical control link between the application software on the desktop computer and the telephone on the desk eliminates the need to physically connect the telephone to the desktop computer. The author distinguishes between the application programming interface and the network telephony service provider. The author assumes the services are provided by NTS R2.2 release and a PBX-based switching service. However, the author uses the term PBX to include switching services provided by key telephone or hybrid systems, PC-based telephony cards, or other appropriate technologies