基于FPGA和DSP的全数字PGC解调系统设计

Design of digital PGC demodulation system based on FPGA and DSP

本文设计了基于FPGA+DSP的全数字相位载波(PGC)解调系统,用于消除双臂干涉型光纤传感器中固有的相位漂移,采用FPGA实现混频相乘和低通滤波环节,采用DSP实现其余的PGC解调环节。在FPGA软件设计过程中,通过使用知识产权(IP)核提高了程序的质量和稳定性。在DSP软件设计过程中,将其余PGC解调环节设计为中断服务程序,接受FPGA产生的中断以完成后续PGC解调过程。浮点数据格式的使用提高了数据的动态范围同时提高了解调精度。实验结果验证了全数字PGC解调系统的设计。

A digital phase generated carrier （PGC） demodulation system based on FPGA device and DSP processor is demonstrated. This system is designed to eliminate the phase drifts in the dual-armed interferometric fiber optic sensors. The multiplier and low pass filter of PGC demodulation are implemented in FPGA device and the subsequent procedures are implemented in DSP processor. In the FPGA software design, the Intellectual Property （IP） core is used to improve software quality and stability. In the DSP software design, the subsequent procedures are designed as interrupt service routine （ISR）, which responds to the FPGA interrupt signal and takes the subsequent PGC demodulation. The use of floating-point data format also improves data range and demodulation precision. Experiment results verify the digital PGC demodulation system design.