The Design Of Digital Down Converter In Bss Receiver

In practice, when there are multiple users in the same channel or the antenna array signal is improperly handled , multiple sources of signal will be mixed in the transmission due to channel coupling.And then the user will receive the impure signal. When the signal aliasing is more serious, the user using commonly receiver will unable to extract useful signal. The role of the receiver which is design with software radio technology based on blind signal separation is to solve the above problem. It could extract the signal needed by user from the received signal. However, as blind source separation has long been influenced by the noise, leading to it has been unable to make a difference in practical applications. In order to make a breakthrough on the receiver design, it has to understand the components deeply.The main idea of this paper is how to research and design the digital down-conversion technology which is a key component of the BSS receiver, so as to laying a good foundation for establishing a common hardware platform of BSS research platform. Firstly, a simple anti-aliasing software radio receiver is presented and the basic structure of the digital receiver is described. Secondly the theoty and method about extraction, interpolation and filter design and so on will be descriped appropriately. Thirdly combined with receiver test on digital down-converter design requirements, the digital down converter parameter is been got, and simulation test is been completed. Finally, a simple separat test is been done by using the receiver hardware platform.The objective of this study is to design a receiver for blind signal separation in two-channel dedicated FPGA-based digital down converter parts. It will be used as a digital front-end of signal receiver in the blind signal separation test and complete the spin-down function after the A/D without distortion. Finally a conclution of a method about how to design a DDC which in BSS receiver effectively during the design should be get.At last, an experiment on BSS with the designed parameters should be maked and the results should be inspected. Test results show that on the contion of narrow-band signals or lineared mixture, using the method and conclusion bansed on the design of DDC on FPGA,the receiver could separate the mixed signal effectly.