基于FPGA的频谱分析仪功率触发模块设计

FPGA-based design of the power trigger module in spectrum analyzer

有效的实时功率触发是很多频谱分析工具中缺失的项目,因为传统扫频模式在时域触发事件开始扫描,无法捕捉到触发前发生的事件,不适合完成实时触发。本文提出了一种全数字式的设计,采用XILINX公司的Virtex-5 FPGA搭建功率触发模块,在具有数字采集的系统中能够以数字方式表示和处理信号,并配以大的内存容量,可以捕获触发前及触发后发生的事件,与预设的触发功率进行比较。该设计实现了传统扫频结构难于实现的实时功率触发功能,并通过仿真验证了它的正确性,在实时频谱分析中有重要意义。

Effective real-time power trigger is missing in many of the spectrum analysis tools, because the traditional sweep Spectrum Analyzer start scanning after the trigger event in time domain, and cannot capture the trigger event occurred before. It is not suitable for real-time triggers. This paper presents an all digital design, using XILINX＇s Virtex-5 FPGA to build a power trigger module, with a large memory capacity, the module can express and process digital signals in the system with digital acquisition. The module can capture the events before and after the trigger is triggered to, and compare these values with the default trigger power. This design achieve real-time power trigger functions, which is difficult to achieve in traditional sweep Spectrum Analyzer. This is important in real-time spectrum analysis.