The Application And Research Of Digital Audio Broadcasting In Frequency Modulation Band(FM-CDR)

Digitalization has become the inevitable trend of the development of radio and television in the world.An important technology foundation of broadcasting digitalization is the technology of digital audio broadcasting.This thesis mainly studies the technology of the digital audio broadcasting in frequency modulation band(FM-CDR).The transition from analog to digital broadcasting in FM without the use of frequency resources and keep the original FM transmitter and antenna system case,using FM-CDR technology,which can transmit digital broadcast programs,so as to realize analog program and digital program broadcasting at the same time.At present,the main digital audio broadcasting standards in the world have three kinds of digital audio broadcasting standards,such as European DAB/DAB+,American HD Radio,and DRM/DRM+ of the world broadcasting union.These three kinds of digital audio standards are not suitable for application in our country because of their own limitations.In 2011,the science and Technology Department of SARFT set up CDR(China Digital Radio)working group to build a digital audio broadcasting system that is suitable for China's national conditions and has independent intellectual property rights.In August 2013,China issued the channel standard and reuse standard of CDR frequency band.The related industry standard has been issued successively:"the first parts of FM band digital audio broadcasting:digital broadcasting channel frame structure,channel coding and modulation","FM frequency digital audio broadcasting part second:multiplexing".FM-CDR in China adopts DRA+ as the source coding algorithm,an extended version of DRA,to provide high quality audio service.It adopts flexible spectrum configuration to solve the problem of insufficient spectrum resources in China,and the system architecture supports gradual evolution,supporting various kinds of data value-added services.The coded orthogonal frequency division multiplexing(COFDM)technology effectively overcomes the multipath interference,and enables the stable broadcast of high quality radio signals in the mobile state,which is an important development direction of the terrestrial digital broadcasting.The technical standard of CDR is discussed in detail,along with its transmission principle,system structure and performance,channel properties,channel,coding and other key technologies.CDR broadcasting's digital services can achieve programs such as program related services,voice services and other data services while broadcasting audio programs.The paper gives a discussion to the sending way of CDR data business,value-added business mode and business operation mode.At the end,the concrete implementation of the FM-CDR system is expounded with the background of the radio digital coverage project of the central broadcasting program.This project is also the first large-scale pilot broadcast since the standard promulgation of frequency band digital audio broadcasting.To further grasp the performance of the pilot project in central broadcasting digital wireless coverage,and in FM band digital audio broadcasting coverage of the relevant local characteristics,road tests for transmitting stations coverage is proceeded.The coverage and interference of digital audio broadcasting and of analog simulcast,had been understood,and a lot of experience for the future implementation of the project and FM band digital audio broadcasting network planning is accumulated.