摘要
用宽带脉冲代替传统的正弦脉冲进行叠加法测量 ,可以在一定程度上降低大面积水声材料自由场测量中的低频限。然而 ,这个声脉冲的脉宽和频谱受到发射换能器和功放响应的严格制约。文中将数字信号处理中的反滤波技术应用于水声材料性能的测量中 ,改进了这一修正的测量方法。先对水听器接收到的声脉冲进行数据采集 ,计算出测量系统的频率响应 ,然后对该系统进行反滤波处理 ,结果 ,使原来的声脉冲得到了时域上的压缩 ,扩展了测量频段 ,特别是大大降低了对有限尺寸样品测量的截止低频限。文中首先简要介绍了反滤波的原理 ,然后描述了测量系统和数据采集与处理过程 ,最后给出了对实际材料样品的测量结果与理论值的比较。
The low frequency limitation of measurements in free field for large area underwater acoustic materials can be reduced to a certain degree by the superposition method, in which a broad band pulse is used to replace the traditional sine pulse. However, the pulse duration and the frequency bandwidth are strictly confined for frequency response of transmitting transducer and power amplifier. Inverse filter, one of the digital signal processing techniques is applied to the measurements to improve the modified measuring approach. At first, the data acquisition to the sound wave pulse received by a hydrophone is carried, then, the frequency response of measurement system is calculated, and the inverse filter processing is done for the system. As a result, the prime sound wave pulse is compressed in time domain and the measuring frequency bandwidth is expanded, especially, the lower cut off frequency of the measurements for finite size of samples is greatly decreased. The principle of the inverse filter is briefly introduced. Then the measurement system and the processing programs are described.Finally, a comparison between the measured results and the theoretical values of an actual material sample are shown.
出处
《数据采集与处理》
EI
CSCD
2000年第1期102-106,共5页
Journal of Data Acquisition and Processing
关键词
水声材料
测量
反滤波
脉冲压缩
数据采集
underwater acoustic materials
measurements
digital signal processing
inverse filter
pulse compression
