Study And Realization Of Software Radio IF Receiver

Since 1990s, wireless communication has advanced rapidly in the world. No matter in the military or civil wireless communication, a lot of new systems and modes have appeared in various frequency channels. They provide kinds of services to the people, satisfying various requirements of our society. Whereas, it has already become a great difficulty need to overcome that the interconnection and compatibility should exist in multi frequency channel wireless communication and multi mode wireless communication. On the other hand, after the migration from analog to digital, and from fixed to mobile, radio systems are undergoing the third revolution from hard-wired radios to software-defined radios (SDR). SDR, based on opening architecture, applies software engineering technique to realize various communication systems, those systems have the greatest flexibility and adaptability and can effectively solve the interconnection and compatibility in wireless communication. Consequently, SDR has been favored by the people since it was brought forward.This paper has carry on comparatively deep researchs to several key technologies of SDR. Firstly, it probes into several kinds of common sampling in SDR, compares and analyzes their each characteristic. Secondly, it discusses multi rate digital signal process (MRDSP) technology in SDR, emphasis is put on the analysis of band pass signal orthogonal sampling structure. Thirdly, several basic structures of SDR are introduced, the AM and FM demodulation algorithms for IF receiver system are discussed, and the demodulation courses of AM and FM are simulated.Moreover, this paper explores how to make use of DSP, CPLD, Digital down conversion (DDC) device, ect, to construct a SDR IF receiver which can carry out the demodulation function of AM signal if AM demodulationprogram is downloaded.