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频率是超声波换能器(简称探头)的一个重要参数,探头的近场长度、超声波长、扩散角、分辨率等都与频率有关。下面介绍测试探头频率的几种方法。一、传输电路法。频率单纯的探头,在谐振频率附近其等效电路可用图1表示。分析图1的等效电路,可见探头的阻抗是随着频率的变化而变化的。传输电路法就是利用探头这种特性来测量其串联和并联的谐振频率。传输电路法又可分为定电压法和定电流法。由于定电压法要求有输出阻抗很小的
Frequency is an important parameter of the ultrasonic transducer (referred to as the probe). The length of the near field of the probe, the length of the ultrasonic wave, the diffusion angle and the resolution are all related to the frequency. Here are some ways to test the probe frequency. First, transmission circuit method. A simple frequency probe, its resonant frequency near the equivalent circuit shown in Figure 1. Analysis of Figure 1, the equivalent circuit, we can see the impedance of the probe is changing with the frequency changes. Transmission circuit method is to use the probe to measure the characteristics of its series and parallel resonant frequency. Transmission circuit method can be divided into constant voltage method and constant current method. Due to the constant voltage method requires a small output impedance