基于STM32与FPGA的导波激励源设计

Design of Excitation Source Circuit for Guided Waves Based on STM32 and FPGA

基于STM32和FPGA设计了一种专门用来进行超声导波管道无损检测的信号发生器。该激励源由STM32、FP-GA、D/A转换电路以及低通滤波电路组成。基于DDS基本原理,阐述了超声导波专用DDS模块设计方法,并给出了STM32与FPGA的接口电路、D/A转换电路及滤波电路的设计方法。其中STM32为整个系统控制核心,主要负责送频率控制字,FPGA主要为了产生DDS波形。FPGA输出的数字信号经D/A转换及低通滤波后即可得所需激励信号。实验结果表明输出的信号噪声小、精度较高、频率可调,能方便地用于管道超声导波检测。

A signal generator, used for exciting ultrasonic guided waves in pipeline is designed based on STM32 and FPGA. The excitation source consists of STM32, FPGA, D/A conversion circuit and a low pass filter circuit. Based on DDS, the design method of DDS module is elaborated. SM32 and FPGA interface circuit,D/A conversion circuit and the filter circuit arc designed. STM32 is the central proces- sor and primarily responsible for transmitting frequency control word. FPGA is mainly used to generate DDS waveform. The output data of FPGA are converted by a D/A,then go through low-pass filter,to get the needed signal. The experiment results show that the output signal is low noise, high precision and the frequency can be set as required. It can be conveniently used to ultrasonic guided wave detection in pipeline.