基于并行传输网络模型的声学参数测量仪器

An acoustic-measurement device based on parallel-connected transmission network model

报道一种新开发的基于电-声/声-电转换传输网络模型的声学测量仪器。该系统的物理模型由一系列并联等效电路组成,可用来更为准确地描述实际声学测量过程。当声波换能器被包含有多个频率分量的信号子波激励时,并联网络中的每一个等效电路将具有自己独特的辐射阻和辐射质量,且每个频率分量将独立地作用于对应等效电路的电学端/力学端。力学端/电学端的累积输出就是声换能器输出的声/电信号子波。该系统在理论上考虑了换能器的电-声/声-电转换、驱动电压信号子波和传播介质特性对测量的声信号的影响,其物理实现采用高分辨率、高采样率数据采集和虚拟仪器技术,使该系统可以保证声信号的精确测量和处理。作为声学测量中的一个应用实例,用薄球壳压电换能器的瞬态响应模型对系统的功能进行了测试。实验测量结果与理论计算基本相符,且具有较高的测量精度。

A newly developed acoustic-measurement system based on an electric-acoustic/acoustic -electric conversion transmission-network model, which is a combination of a series of parallel-connected equivalent-circuits, is reported. This model can be used in description of acoustic-measurement process more accurately. When the acoustic-transducer is excited by a electric/acoustic signal wavelet with multiple frequency components, each circuit would have a distinctive radiation resistance and a radiation mass. Each frequency component would act independently on the electric/mechanic-terminals of the transducer. A cumulative signal-output from the mechanic/electric-terminals is measured as the overall acoustic/electric output of the acoustic-transducer. This system in theory considers the effects of electric-acoustic/acoustic-electric conversions of transducer, driving-voltage signal wavelet and the propagation medium on measured acoustic-signals, and its physical realization adopts high resolution/sampling rate data acquisition and virtual instrument technologies. Therefore this system can guarantee the accurate measurement and processing of acoustic-signal wavelet. As a prototype example in practical measurement, we have tested the system with a realistic application. The results of measurement are basically in agreement with the theoretical calculation,and highly accurate in measurement.