摘要
相关法超声波流量检测方法,能有效利用超声波脉冲的整体信息进行时差测量。但针对传统相关法的超声波流量测量过程中,等振幅周期信号具有重复性,波形在利用相关法计算的结果不能准确地反映出信号的时间差的这一缺点。采用改进的相关法,使用FPGA(现场可编程门阵列)发出一种特殊调制的驱动脉冲,使超声波探头在需要的一定周期内发射出幅度调制的波形,克服等振幅周期信号在做相关后时间差判断不准的情况,并且硬件平台相对简单即可达到理想效果。通过实验可以证明,控制激励探头的脉冲信号的占空比,可以改变发射波形的幅值特性,得到适合相关运算的波形,达到预期的测量效果。
Uhrasonic flow detection method based on correlation method can effectively use ultrasonic pulse to measure overall information of time difference. But in the ultrasonic flow measurement process based on traditional correlation method, the equavalent amplitude cycle signal is repeatable so that waveform in the use of correlation method calculation results can not accurately reflect time difference of the signal. An improved correlation method is used. The ratio modulation drive pulse is emitted by using FPGA （field programmable gate array） to make ultrasonic probe to emit a waveform with amplitude modulation in a certain period to avoid the situation of inaccurate judgment of the constant amplitude periodic signals in the correlation processing time, but achieve an ideal effect by relative simple hardware platform. The experiments prove that the amplitude characteristics of emission waveform can be changed by controlling the duty cycle of pulse signal of incent probe. The waveform suitable for correlation operation was acquired and the expected effect of measurement was achieved.
出处
《现代电子技术》
2013年第7期108-110,114,共4页
Modern Electronics Technique
基金
国家自然科学基金资助项目:管道应力集中区域磁检测方法研究(61141004)
关键词
超声波流量测量
相关法
驱动脉冲
波形衰减
ultrasonic flow measurement
correlation algorithm
drive pulse
waveform attenuation
