一种用于超声检漏探头激励的任意波形发生器

超声检漏作为一种新型检漏方法,越来越多地应用于工业现场.为满足超声检漏中超声探头激励的需要,介绍了一种任意波形发生器的设计,利用直接数字式频率合成(DDS)技术,以FPGA作为主要器件,并辅以必要的放大、滤波电路,实现任意波形的产生.通过串行接口,用单片机来设定频率和幅度的大小以及波形的选择;FPGA用来改变DDS频率控制字,并由FPGA来实现波形表生成和频率控制;将FPGA产生的波形数据送入到AD7524进行D/A转换,通过低通滤波器和集电极开路电路来提高输出波形质量并增强其带负载能力.最后给出了本设计产生的正弦信号与函数发生器产生的正弦信号的频谱分析比较.

Arbitrarywaveform generator for exciting ultrasonic transducer in leak detection

This paper introduces the principle of digital waveform generator and design a digital function generator based on direct digital synthesizer (DDS) technology used FPGA and necessary analog circuits.By serial communication,the single-chip microcomputer is used to set the frequency and amplitude,as well as the choice ofwaveform;FPGA to change the word of DDS frequency control and to realize the waveform table's generation;The profile data which FPGA produces is sent into AD7524 to carry on the analog-to-digital conversion;The latter level uses the low pass filter and the OCL amplifier to improve the wave quality and to enhance its ability to take the load.At last,the paper gives a frequency analysis between the sine wave produced by the circuit in this paper and the sine wave produced by a signal generator.