Design And Implementation Of Mid-frequency Band Receiver In OFDM System

In this project, according to the theory of OFDM, the theory of bandpass sampling, the theory of multirate digital signal processing and the theory of optimal receivers, we gave a wideband mid-frequency sampling processing structure. This structure realized the conversion of the OFDM signal from mid-frequency to base band and from the analog domain to the digital domain and its sychronization. The high quality of ASICs and the high flexibilily of FPGAs were made best use of in this structure.In this paper, we introduced the OFDM transmission system that the mid-frequency band receiver works in, and then discussed the relative digital signal processing theories, then designed the circuit and analyzed the technical problems and their solutions. Designing and analyzing of the main modules of the circuit such as AGC, ADC,DDC, the sampling filter, were presented in details. Implementation of the synchronizer in FPGA was also discussed. The mid-frequency band receiver was implemented with the desirable characters.