ITU R Telegraph transmission ITU R系列准则列表
标签： transmission ITU Telegraph 准则
上传时间： 2014-12-03
上传用户：wab1981
The files in this directory comprise ANSI-C language reference implementations of the CCITT (International Telegraph and Telephone Consultative Committee) G.711, G.721 and G.723 voice compressions. They have been tested on Sun SPARCstations and passed 82 out of 84 test vectors published by CCITT (Dec. 20, 1988) for G.721 and G.723. [The two remaining test vectors, which the G.721 decoder implementation for u-law samples did not pass, may be in error because they are identical to two other vectors for G.723_40.]
标签： implementations directory reference comprise
上传时间： 2014-01-22
上传用户：Breathe0125
For nearly a hundred years telecommunications provided mainly voice services and very low speed data (Telegraph and telex). With the advent of the Internet, several data services became mainstream in telecommunications; to the point that voice is becoming an accessory to IP-centric data networks. Today, high-speed data services are already part of our daily lives at work and at home (web surfing, e-mail, virtual private networks, VoIP, virtual meetings, chats...). The demand for high-speed data services will grow even more with the increasing number of people telecommuting.
上传时间： 2020-05-27
上传用户：shancjb
The dictionary definition of telecommunications is ‘communication over long distance by cable, Telegraph, telephone or broadcasting’, but since its initiation over 100yearsagothingshavemovedrapidly.Telecommunicationsisnowaverycomplex industrywithmanydifferentpressures,operatinginahighlydynamic environment.It is best viewed as part of a wider industry known as information and communication technology (ICT). The purpose of this chapter is to explain where telecommunication fits in, to highlight some of the complexities – hopefully to simplify them – and to position the industry in today’s dynamic business environment.
标签： Telecommunications Understanding Business
上传时间： 2020-06-01
上传用户：shancjb
Telecommunications is today widely understood to mean the electrical means of communicating over a distance. The first form of telecommunications was that of the Telegraph, which was invented quite independently in 1837 by two scientists, Wheatstone and Morse. Telegraphy was on a point-to-point unidirectional basis and relied on trained operators to interpret between the spoken or written word and the special signals sent over the Telegraph wire. However, the use of Telegraphy did greatly enhance the operations of railways and, of course, the dissemination of news and personal messages between towns.
标签： Telecommunications Understanding Networks
上传时间： 2020-06-01
上传用户：shancjb
Digital radios have undergone an astonishing evolution in the last century. Born as a set of simple and power-hungry electrical and electromechanical devices for low data rate transmission of Telegraph data in the Marconi age, they have transformed, thanks to substantial advances in electronic technology, into a set of small, reliable and sophisticated integrated devices supporting broadband multimedia communications. This, however, would not have been possible unless significant progress had been made in recent decades in the field of signal processing algorithms for baseband and passband signals. In fact, the core of any modern digital radio consists of a set of algorithms running over programmable electronic hardware. This book stems from the research and teaching activities of its co-authors in the field of algorithmic techniques for wireless communications. A huge body of technical literature has accumulated in the last four decades in this area, and an extensive coverage of all its important aspects in a single textbook is impossible. For this reason, we have selected a few important topics and, for ease of reading, organized them into two parts.
标签： Communications Algorithmic Techniques Wireless
上传时间： 2020-06-01
上传用户：shancjb
