Since the 1990s, as digital technology and the rapid development of Internet technology, digital consumer electronics market is very promising. In order to enable the radio to television and the Internet competition and in mass media industry worldwide, jockeying for broadcasting professionals began to digital technology and network technology applied to the broadcasting system. So digital audio broadcast (DAB, digital-audio broadcasting) has emerged.
Broadcast digital progress
From broadcast engineering technology development phase, the audio broadcasting can roughly be divided into three phases: the first phase was started in 1920 of the am radio (AM). Am broadcasting as a result of the use of radio frequencies to a narrow, be it reproduces the highest frequency only five or six kHz, sound treble not rich timbre is also not very good.
The second stage began in the 1940 's FM (FM). Because of its frequency band width than the am broadcasting, the reproduction of sound and high frequency enrichment, lifelike. In addition, its noise less am broadcasting.
The third phase is the phase of digital audio broadcasting. Nowadays people talk about the most is the digital TV, as everyone knows, the first European standard for broadcasting digital broadcasting — Yuli card standard, but earlier than TV digital broadcasting standard. Digital audio broadcasting development study launched by the EC, first in 1988 and 1 January, officially, as the International Telecommunication Union (ITU, International Telecommunications Union) accreditation of terrestrial digital audio broadcasting system. Secondly, to the end of the 20th century, the International Telecommunication Union approved a set of digital audio broadcasting system has entered a phase of preparation for the test run. This is the world wide satellite group (WorldSpace Corporation) introduced the satellite digital audio broadcasting system. This system consists of three satellites in geosynchronous orbit satellite, broadcast uplink station, digital receivers and ground control operations network. This system has advantages and great features and will be in the 21st century global dissemination areas showed tremendous power.
Digital audio broadcast of unique charm
First of all, good sound quality. And compared with traditional broadcasting services, digital audio broadcasting to reduce sound distortion and improve sound quality. Digital radio broadcast sound to match with the compact disc, no noise and interference. If the audience to listen to music or songs, they will produce the concert's real experience.
Second, the radio volume, contains a large amount. Because digital broadcasting each radio frequency band occupied by a very narrow, so the same available frequency band, it can accommodate the number of radio stations. In addition, the use of digital broadcasting, with a frequency above can hold more information. For example, the radio station will play normal FM or FM radio at the same time send digital information. In other words, the use of digital radio or holding such a device can receive compact discs sound quality of digital signals, and ordinary radio listeners still able to listen to broadcasts.
Once again, the process of autonomous control playback. We use traditional radio, can only be a passive acceptance of the content of the broadcast radio, once missed a show, will not be able to enjoy again, unless radio replay. But after using digital audio broadcasting, the situation is quite different. Digital radio may forever change the way we listen to the radio. It may be timely to pause and fast-forward digital broadcasts. If in the middle to the calling program, you can press a key to pause the program, when the call ends before continuing. Currently, other entertainment platform has paused, recording, and fast forward functionality, the emergence of digital audio broadcasting will enable people to traditional broadcasting.
Finally, digital audio broadcasting, there are other powerful features, you can also monitor the audience, such as what people hear and listen to them when they are downloaded, they considered how to play songs and so on. This feature makes the radio to the fastest speed of change in their programmes to suit the needs of the audience. Once you have a portable digital radio, people will be able to watch movies, read news, download games and more.
From listening to the radio broadcast of the "look"
At present, digital audio broadcasting in the world-wide application in the increasingly widespread, 36 countries have adopted or are in the test and test. 16 countries in Europe have been broadcast on digital audio broadcasting. September 1995, the United Kingdom Broadcasting Corporation (BBC) first digitally audio broadcasts broadcasts. Now the United Kingdom there are 10 national commercial radio and broadcasting radio stations in the United Kingdom, London 2.2 taxi's are mostly equipped with a digital audio receiver, has more than 70 per cent of the population can receive digital audio broadcasting. While Germany is planned for 2010 off the FM radio, complete with digital audio broadcasting. In Asia, Singapore is only able to provide digital audio broadcasting across the country. But in China, while in 1996 has begun in Beijing and Guangzhou for digital audio broadcasting pilot work, but a clear digital audio broadcasting development policy still makes the absence of overall development of the affected country.
There is also a digital broadcasting system has also been an official being broadcast around the world, this is the satellite digital audio broadcasting system. Satellite digital audio radio addition and digital audio broadcasting the same advantages, there are other advantages. For example, it covers an area of large, any terrestrial broadcasting system cannot be compared, especially on a global, national coverage of the saloon, the more important. It investment and operational costs are relatively low, it is mainly used for ground uplink station construction costs. It and the national FM radio network construction investment ratio of 1: 200, and the national FM radio network operating expenses ratio of 1: 100. In addition, it broadcasts may act according to the different needs of broadcast quality sound from the economic point of view, any select broadcast bandwidth such as broadcast music festivalMesh, to select 128K/s bitrate, so you can get CD-like sound quality, and for most of the broadcast, you can select a lower bitrate, and at the same time, select the types of programmes and programmes of bandwidth format combinations can be easily completed. First enter the broad market is a broad international co., Ltd., a United States company and Sirius XM company, etc. The former is engaged in the United States market, the global digital audio broadcasting business satellite company.
Since the future is digital audio broadcasting, digital radio or receiver market demand will increase significantly. United States Consumer Electronics Association in January 7 June, the International Consumer Electronics Show in Las Vegas report said that the satellite broadcasting user is more than one million per year of high speed growth, 2003 United States only 150 million users, 2004 increased to 320 million, this year you will grow to 550 million. Responsible for the United Kingdom Broadcasting Corporation · Matthew Bannister, said the company's digital radio technology in the United Kingdom in a leading position. He also speculated that in the next three years of the commissioning phase, the United Kingdom audience will reach 60% of the total population of the country. 2001 Japan Broadcasting, and more than 40 manufacturers and related companies, such as 10, convened a conference sponsor, has established the "digital radio promotion Association", entered the broadcast ready stage. World wide group Beijing Office Chief Representative said that the world wide group will fully in accordance with the rules of the China entered the Chinese market is being wound up. If a smooth entry into the Chinese market, expected within five years of world wide system receiver community ownership can reach more than 500 million units. （
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