Research Of Transmission Technology Of Digital Television Terrestrial Broadcasting System

Digital TV actually means a kind of television broadcasting system, which uses digital technology to create, transmit, receive, process and store the programs. Compared with conventional analog broadcasting systems, digital TV has better anti-jamming performance and higher spectrum utilization. There are three mature standards of DTTB (digital television terrestrial broadcasting) system in the world, which are ATSC(USA Trellis-Coded 8-Level Vestigial Side-Band), DVB-T(Europe, Digital Video Broadcasting-Terrestrial) and ISDB-T(Japan, Terrestrial Integrated Service Digital Broadcasting). Each has their own character. Our own terrestrial digital broadcast transmission standard is issued in 2006, in which it provides the frame structure, channel coding and modulation modes.Currently, DVB-T gets the highest evaluation among all the tested standards of several countries in the broadcasting industry, along with its mature technology. DVB-T system adopts Coded Orthogonal Frequency Division Multiplexing(COFDM) technology. Both the insert of scattered pilot and the cycle characteristic of data block make the channel estimation and equalization algorithm very easy which this paper will deal with, but meanwhile the pilot reduces the spectrum utilization. The performance of DVB-T in multi-channel will be shown by my simulation using Matlab.Concerning our complex terrain, Chinese DTTB contains single-carrier and multi-carrier two programs; the later is developed by DMB-T (Terrestrial Digital Multimedia Television Broadcasting) proposed by Qinghua University. DMB-T uses Time Domain Synchronization OFDM(TDS-OFDM) technology. Along with advanced OFDM, the PN sequence frame head applied by TDS-OFDM can be used to synchronization, channel estimation and equalization. No inserted pilot can reduce the expenditure to enhance the spectrum utilization. Though there is no cycle characteristic of its data block and the PN frame head will introduce inter-symbol interference, all this can be solved after several iterative operations and then the result is satisfactory. This paper researched the characteristic of PN sequence, used it to do channel estimation and equalization, also have simulated it under multi-channel.There are different editions of the advantages and drawbacks between DVB-T and DMB-T. This paper will give my learning experience and conclusions based on my comparison between DVB-T and DMB-T channel estimation and equalization.