Signal Demodulation Algorithm Based On Software Radio Architecture

With the development of modern communication technology and Very Large Scale Integrated Circuits (VLSI) technology, the concept of Software Radio is becoming highly valued. Software-defined radio technology is to build a general, standardized, open hardware platform,In this platform, we can define sorts of functional unit via software ,and then based on these function ,build a flexible, efficient and new communication system. However the FPGA (Field Programmable Gate Array) provide a very good platform for the realization of the software algorithm. So the FPGA implementation processing of modulated signal demodulation algorithm based on the Software Radio Technology become an important topic. Around this topic, this paper studied several modulating signal demodulation algorithm methods on FPGA. The subject of this paper is DSB, FM, BPSK modulating signal demodulation algorithm. Detail works is as below:This paper, Using serial programming Structure and Pipeline Design Method, realized the filter design which is using in common in Software Radio. Finally, It's proved to meet the design requirement.This paper also realized the Costas FPGA design that is the key component in the Carrier synchronization technique. And choose the Complex signal processing technology of Costas Loop structure through the theoretical simulation. Compared with the traditional Costas Loop, this kind of loop has the features which have wider locking bandwidth and shorter locking time. Compared with the traditional Costas,the locking bandwidth of complex Costas loop is boosted, and the rate is 65%. On the contrary, in the case of identical frequency difference, only 1/6 locking time is needed.This paper realized the FPGA implementation of CORDIC algorithm's arctangent operations. The calculation results are the same with the theoretical values in the precision requirement of 10-4 by hardware simulation. This result shows the design meet design requirement.This paper also completed the FPGA implementation of DSB, FM, BPSK signal demodulation system by describing the system's RTL scheme with Verilog HDL which is one of description language for RTL. Finally decided the demodulation system simulation and the result showed in the certain parameters the demodulation system can correctly restore the baseband signals. It meet the design requirement.The paper designed the interface program of hardware debugging platform-XtremeDSP Development Kit-IV provided by Xilinx, connects and debugs the DSB demodulation system designs on the hardware platform.