基于FPGA的可变带宽基带信号回放系统设计

Design of variable bandwidth baseband bignal playback system based on FPGA

针对不同带宽基带信号回放到目标中频的需求,设计了一种可变带宽基带信号回放系统。该系统以FPGA为核心数据处理单元,通过配置高速数模转换芯片AD9122和时钟芯片AD9516完成基带信号的回放功能。为解决不同带宽基带信号采样率与DAC发射速率不匹配的问题,设计了一种多速率处理算法,采用多级HB滤波器、CIC滤波器和Farrow滤波器级联的结构实现了任意倍的采样率转换功能。算法仿真和实际测试结果表明该系统能够以较少的资源消耗将1 kHz~20 MHz的可变带宽基带信号回放到目标中频上,回放信号无杂散动态范围不低于60 dBc,满足实际通信系统需求。

Requirement for playback of baseband signals of different bandwidths to the target intermediate frequency,a variable bandwidth baseband signal playback system was designed.The system took FPGA as the core data processing unit,and completed the playback function of the baseband signal by configuring the high-speed digital-to-analog conversion chip AD9122and the clock chip AD9516.In order to solve the problem that the sampling rate of baseband signal with different bandwidth does not match the transmission rate of DAC,a multi rate processing algorithm is designed,The cascade structure of multi-stage HB filter,CIC filter and Farrow filter is adopted to realize the function of arbitrary multiple sampling rate conversion.The algorithm simulation and actual test results show that the system can play back the 1kHz~20MHz variable bandwidth baseband signal to the target IF with less resource consumption The playback signal has spurious free dynamic range not less than 60dBc,meeting the requirements of the actual communication system.