基于互相关的测量声波飞渡时间的研究

摘要

According to the temperature of the gas medium field acoustic measurement principle, only to realize acoustic travel time of high accuracy, rapid measurement, in order to ensure temperature field inversion measurement precision and measurement of real-time. Therefore, combined sequence of pseudo-random code technology with mutual correlation analysis method, design of a acoustic travel time and a high degree of accuracy, rapid measurement system, and simulation tested. The simulation results show that the proposed scheme is feasible and effective. That when not to join the pseudo random sequence, although there are correlation between acoustic emission and receiving signals, but there will be a continuous repetitive peak, unable to obtain acoustic loose time ; at the same time, not sampling precision, the higher the better. When the carrier frequency is 40kHz, the measuring accuracy of the sampling frequency is the highest and the speed is the fastest when the 200kHz is selected, and the measurement accuracy is less than 10, which can meet the requirement of the high precision and real time measurement of acoustic temperature measurement.%根据气体介质温度场声学测量原理可知，只有实现声波飞渡时间的高精度、快速测量，才能保证温度场反演测量的高精度和测量的实时性。为此，将伪随机序列编码技术与互相关分析方法相结合，设计了一种声波飞渡时间高精度、快速测量系统，并对其进行了仿真研究。仿真结果表明：该方案是可行的和有效的。即当不加入伪随机序列时，声发射与接收信号间虽有相关性，但会出现连续重复峰值，无法求得声波飞渡时间；同时，并非采样精度越高越好。当载波频率为40 kHz时，采样频率选取200 kHz时的测量精度最高且速度最快，且测量精度绝对误差小于10，能够满足声学测温的高精度和实时测量的要求。