DAB、DAB+介绍

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DAB、DAB+、DMB介绍

DAB家族，包括针对数字音频的DAB和DAB+，以及针对移动电视的DMB标准，用于地面数字广播信号的传输，具有灵活、全球化和开放的特性。

最早，DAB（Digital Audio Broadcasting）在20世纪80年代被制定出来，它是基于MPEG Audio Layer II编码，该编码方式目前仍然在数字音频领域中得到普遍应用。

随后，MPEG Audio Layer III编码，也就是大家熟知的MP3，统治了数字音频领域。尽管MP3仍然是广播领域最成功的技术，但MP3已经被更有效和品质更好的AAC（MPEG-4）所取代。

集成AAC到DAB中，意味着更高效率，在更低的比特率条件下提供相同的声音品质，从而诞生了DAB+。

另外更重要的创新是，把视频和多媒体传输功能添加到数字音频广播中，使得DAB成为数字移动电视平台DMB (Digital Multimedia Broadcasting) ，支持多媒体数字广播。

无论DMB还是DAB+，都兼容DAB。换句话说，三者物理层相同，只是添加了新的传输和应用协议，此外还添加了纠错控制层。所有这些技术特征都基于相同的架构，但彼此独立，可以在特定场合复用成为一个整体。

Introduction to DAB, DAB+

The DAB family of standards includes DAB and DAB+ for digital radio and DMB for mobile TV. They are flexible, global  and open standards and are a means for transmission of terrestrial digital radio signals.

When the original DAB (Digital Audio Broadcasting) was first developed in the late 1980s, it was based on MPEG Audio Layer II coding, which is still commonly used in broadcasting today.

Since then, MPEG Audio Layer III, better known as MP3 has conquered the market of digital music players. Even though still the most successful technology on the market, MP3 has been overtaken in efficiency and performance by MPEG-4 (AAC). This integration of AAC into DAB allowed higher efficiency, meaning the same audio quality at lower bitrates - hence the birth of DAB+.

Another important innovation was the addition of video/multimedia capabilities to Digital Audio Broadcasting, allowing DAB to become a digital mobile television platform DMB (Digital Multimedia Broadcasting) as well as a multimedia digital radio platform.

Both for DMB and DAB+ the technical basis remains DAB. In other words, the physical layer is still the same, just new applications, new transport protocols and a second error control coding layer was added. All three technologies can therefore be used alongside each other on one multiplex and basically use the same infrastructure, so there is a whole range of possible multiplex scenarios.