Digital Down-Converter Multi-stage Decimation Filter Design

Software radio is a new technology developed in the1990s which had been penetrated intothe commercial radio and other electronic technology field from military communications. Itsbasic idea is to change the radio signals digital and use software technology to meet the variouskinds of radio technology requirements. It breaks through the drawbacks of traditional softwareradio, stressed on flexible, reconfigurable software modules. It is made clear in TD-SCDMAsystem that software radio technology must be used to implement the system.Direct Digital Control, based on software radio and digital signal processing as its core, is abrand-new mobile communication structure. This paper gives a detailed introduction to the basictheory of software radio in sampling techniques, multi-rate signal processing and filter principle.With the in-depth study of third-generation mobile communication technology TD-SCDMAtechnology on this basis, the mathematical model of Direct Digital Control has been derived anddesigned. Focused on the design with multi-level decimation filter and digital down-converterdesign based on Matlab software design digital down converter in a variety of filter modules,complete system. Simulation results show that the system digital down conversion, reducing thedata rate of signal distortion in the downconversion process.,This paper, the design of the digital down-converter multi-stage decimation filter, the3Gmobile communication signal received on the air for digital down conversion, the value ofpractical application and promotion of value..