Implementation Of Software Radio On The Programmable Logic Platform

The traditional radio receivers rely on the hardware strongly, and the flexibility to different communication systems and adaptability to different communication signals are bad. The appearance of the SDR (Software-Defined Radio) results in receiver's renovation. The essential idea of the SDR is to establish a universal hardware platform where the A/D converter is moved as closely as possible to the antenna and the radio functions are accomplished by software as much as possible. Because of the limitation of devices, sampling wideband IF signal is a feasible method now.Digital Signal Processing is a widely used technology in communication systems. DSP algorithms were used to be implemented by the ASIC or PDSP (Programmable Digital Signal Processor). Along with the emergence of the programmable logic devices with large scale logic sources, FPGA(Field programmable Gate Array) is now becoming more and more popular in DSP technology. For the application of Software Radio which requires high processing speed and flexibility, it is a good choice to accomplish the signal demodulation on FPGA.This paper places emphasis on the FPGA processing technology of the wideband IF signal receiving. Firstly, the construction of the system and some important technology are introduced. And the IF signal processing platform was established based on the high-speed and high-precision A/D converter AD6644, D/A converter AD9764 and the high performance FPGA-XILINX Virtex-4 XC4VLX25. Secondly, the modules of the digital receiver (including LPF, NCO and demodulating algorithms) are designed, two hardware algorithms are also introduced along with it. Finally, the demodulation of AM, FM and FSK were accomplished on this platform by programming the FPGA.