Design And Realization Of The FFT Processor And The Path Estimating Arithmetic On DVB-T

At present, when the communication technology is developing more and more quickly, the DVB-T (Digital Video Broadcasting-Transmission) technology has been used widely in Europe. At the meantime, it will make the technology possible which will be used for Electronic commerce, bank service, and internet browse on video net. The transmission mode of DVB-T system contains 2k mode (2048 points) and 8K mode (8192 points), which transmitting capacity is similar to the wired television system in theory, and the signal can be overplayed the whole area. DVB-T accepts OFDM multi-carrier modulation, by which we can make the sufficient use of available spectrum resources, and the effect of its transmission is very good. This essay will complete the design and realization of the FFT processor on DVB-T with Modelsim and Synplify software, and then it will make a research of the channel estimating algorithm.In the essay, we take Verilog to design the FFT module of DVB-T system in 2K mode with based-two algorithm and array architecture. When we make the design, the major job is the design of the adder and multiplier arithmetic elements and the design of the whole FFT module's architecture contained with the butterfly arithmetic element and the address generator unit. At last, we make an emulation to FFT module with FPGA(Field Program Gate Array) in Synplify software, and analyze the result of the synthesis data.The result indicates that the highest frequency of the designed FFT module is 45MHz and the use ratio of the LUT is less than 5%. Therefore, the running speed of the module is very high, and the use ratio of hardware resource is very low which are satisfied with the design requirement of DVB-T system.Then this essay will make a research of channel transmission estimation with the channel estimating algorithm based on pilot assist. DVB-T system takes OFDM as the transmission standard, which has a two-dimension characteristic in time domain and frequency domain; therefore, we use the two-dimension linear interpolating algorithm to do the channel estimation in both of time domain and frequency domain. At last, we analyze the performance of the channel estimating algorithm.The result indicates that the two-dimension linear interpolating algorithm is better than the one-dimension linear interpolating algorithm, especially in high signal-to-mask ratio. When the signal-to-mask ratio of the one-dimension linear interpolating algorithm is more than 25dB, the value of MSE keeps stable.However, when the signal-to-mask ratio of the two-dimension linear interpolating algorithm increases, the value of MSE will decrease rapidly, which shows that the estimating performance of the two-dimension linear interpolating algorithm is better, and satisfied with the design need of DVB-T system in 2K mode.The content of this essay will help us to design and realize the DVB-T system based on national standard in the future, which is a good thing.