在光纤布拉格光栅传感系统中,法布里-珀罗(F-P)滤波器是实现波长解调的关键器件。针对模拟控制电路产生锯齿波进行滤波器驱动的速度和频率分辨率不够高的缺点,利用Altera公司的可编程片上系统(SOPC)技术,设计了一个基于FPGA和高速数模转换芯片DAC904的控制电路,并通过后级调理电路处理得到了一个频率为100 Hz、幅值为0~18 V的锯齿波电压信号完成对F-P滤波器的驱动控制。仿真结果表明:利用数字化技术产生锯齿波来控制滤波器的设计方法,可以简化电路设计,提高输出信号的频率分辨率,提高系统运行速度。

In the fiber Bragg grating sensing system, Fabry-Perot(F-P) filter is the key device of wavelength demodulation. Aiming at the disadvantages of speed and frequency resolution with analog control circuit, a control circuit besed on FPGA and high speed analog-to-digital conversion chip DAC904 with the Alteras programmable system on chip(SOPC) technology is designed in this paper. It generates a sawtooth wave voltage signal with a frequency of 100 Hz, and the amplitude of 0~18 V to drive the F-P filter. The simulation results show that the designed method using the sawtooth wave produced by SOPC technology to control the filter can simplify the circuit design, the frequency resolution of the output signal and the operation speed of the system.