采用系统函数分析换能器阻抗测量方法的性能

Using the system function to analyze the performance of transducer's impedance measurement method

在分析传统三电压法测量阻抗优缺点的基础上,提出了一种发射换能器阻抗测量方法,以解决海上单模激发现场检修发射相控阵一致性的难题。该方法仍利用三电压法电路结构,但修改了测量参数。首先介绍了基于系统函数的换能器阻抗测量方法的原理,然后报道了当串联电阻选取不同数值时换能器阻抗测量的结果以及它们与高精度阻抗分析仪测量结果的比较,最后进行误差分析和测量曲线的等效电路参数拟合。通过对它的性能分析可以看到,在保证采样精度条件下,选择阻值相对换能器阻抗偏小的电阻值,其测量精度完全能达到高精度阻抗分析仪的精度。最后,通过对实验测量阻抗曲线的等效电路参数的最小二乘拟合表明,其拟合电参数准确,能应用到换能器匹配网络的设计。

From investigation of the advantages and disadvantages of conventional tri-voltage method,a method for the measurement of the transmitting transducer＇s impedance was presented to solve the difficult problem of examining the consistency of the transmitting phased array on the single-mode excitation sea spot.In the method based on the system function,the circuit structure of tri-voltage method was used but new parameters were measured.The principle of the method was given first.Then when resistors with different nominal values were used in the circuit the measured results for the impedance of transducers were reported.The results were compared with the higher precision impedance analyzer＇s.Finally,the error analysis was performed according to the impedance formula and the equivalent circuit＇s parameters were fitted.Under the condition of guaranteeing the sampling precision,by performance analyzing,the resistor value in series was chosen relatively smaller than the impedance of transducer,the measurement of impedance could achieve the same precision as the higher precision impedance analyzer＇s.Finally,the least square curve-fitting of measured curve indicated that the transducer＇s equivalent electrical parameters could be extracted accurately and used to design the matching network.