Digital Radio DAB

DAB stands for Digital Audio Broadcasting and is a method for the terrestrial digital transmission of radio signals. DAB was designed in the late 1980s. Its main purpose is to provide radio at CD-quality. DAB is proposed by the British Broadcasting Corporation. China ran a trial in Fo Shan city about this DAB. Digital Audio Broadcasting is also known as Eureka 147. DAB is ETSI standard.It is High definition radio project. It is a digital radio technology.

Updated version of DAB is released in 2007.Updated version is call as DAB+ But DAB sounds worse than FM.Main reason for bad sound quality is broadcasters using bit rate levels that are too low. Digital Audio Broadcasting is a Single Frequency Network All transmitters send an unique signal.So tuning is done automatically. A 1.5 MHz for 10 services cover entire country using a single frequency network. So it is 15-20 times more efficient. Normal Audio has 24ms MP2 frames whereas DAB frames are 96ms.

Digital Audio Broadcasting (DAB), also known as Eureka 147, has been under development since the early eighties, has been adopted by around 20 countries worldwide. It is based around the MPEG-1 Audio Layer II audio codec and this has been co-ordinated by the WorldDMB. DAB receivers are selling well in some markets. WorldDMB announced in a press release in November 2006, that DAB would be adopting the HE-AACv2 audio codec, which is also known as eAAC+. Also being adopted are the MPEG Surround format, and stronger error correction coding called Reed-Solomon coding. [2] The update has been named DAB+. Receivers that support the new DAB standard began being released during 2007 with firmware updated available for some older receivers. DAB and DAB+ cannot be used for mobile TV because they do not include any video codecs. DAB related standards Digital Multimedia Broadcasting (DMB) and DAB-IP are suitable for mobile radio and TV both because they have MPEG 4 AVC and WMV9 respectively as video codecs. However a DMB video sub-channel can easily be added to any DAB transmission - as DMB was designed from the outset to be carried on a DAB subchannel. DMB broadcasts in Korea carry conventional MPEG 1 Layer II DAB audio services alongside their DMB video services.