Modeling And Simulation Of Digital Audio Broadcast System And Circuit Design Of Channel Decoder

Digital Audio Broadcast is the third era broadcast after the AM,FM traditional broadcast based on digital technology with digital audio coding,data compression,error correcting coding, and digital modulation.Most of domestic researches on DAB base-band decoding are based on DSP at present.We must make an ASIC design of DAB decoder on base-band facing the huge market.Moreover, the research on transmitting station is very rare in our country.System model in this paper is built based on SIMULINK and MATLAB.The model can Operate at four transmission modes. And it provides test platform for ASIC design of DAB base-band decoding and provides important proof for design of transmitting station.Multipath fading channel and AWGN channel are added to the model.AWGN channel is divided into four cases:E_b/N₀=2.5dB,5dB,10dB,20dB and then discuss and analyze properties of FIC and MSC under the highest and the lowest coding protection level respectively affected by Doppler shift.The others are between the highest and the lowest level.We get BERs of the channel under different conditions at last.A Lena gray image is transformed through the system for intuitive experience of properties of channel.At the last of this paper,circuit design of channel decoding including energy de-dispersal, Viterbi decoder and time de-interleaver is gave out.RTL codes and function simulations have been done.Model Simulation results show that the structures are fully consistent with "Specification of 30MHz-3000MHz terrestrial digital audio broadcasting system" which was issued by The State Administration of Radio Film and Television of China on May 10th,2006,and circuit design of channel decoder work well which is tested by the system model.