In the design of the finger-overlap envelope according to the envelope of wavelet function, it is concluded that the pulse-response function of the interdigital transducer (IDT) for surface acoustic wave (SAW) is identical to the wavelet function. SAW type of the wavelet-transform element is manufactured. A new method of using two wavelet-transform elements to manufacture the reconstruction element of the wavelet transform is proposed. The sources of the element error are analyzed, and the methods for reducing the error are put forward. SAW type of the wavelet transformation element and its reconstruction element have the following three characteristics: (i) the implementing methods of the wavelet transform element and its reconstruction element are simple, and free of complicated mathematical algorithms of the wavelet transform; (ii) because one of SAW element is fast, the response velocities of SAW type of the wavelet transform element and its reconstruction element are also fast; (iii) the costs of the wavelet transform element and its reconstruction element are low, so the elements may be manufactured in a large quantity.

The principle of measuring the quenching-hardness for the machine elements is the Hall zero-magnetic flux type of principle (i.e. a closed-loop principle), and the formula of the steady-state error for the Hall zero-magnetic flux system is deduced, and the conclusion that the larger the amplifier amplification in the Hall zero-magnetic flux system, the smaller the steady-state error is reached.

利用声表面波器件构造了小波变换及重构器件，为小波变换及重构器件开辟了一种新的制造途径。本文主要论述声表面波式小波变换及重构器件的工作原理，并对信号源内阻对声表面波器件的影响和声电再生问题提出了解决方法。

采用霍尔检零原理(即闭环原理)推导出了霍尔检零系统的稳态误差表达式，得出了在霍尔检零系统中放大器的放大倍数越大稳态误差越小的结论。把小波变换技术应用到小电流传感器中，构造的声表面波换能器脉冲响应函数等于小波函数，从而制造出了声表面波式小波变换及重构器件，该器件可有效滤除小电流传感器的干扰信号。霍尔检零系统可以补偿温度和霍尔元件恒流源电流的变化对测量的影响。

采用了平行板电容器式原油水份传感器，使得原油水份传感器便于清洗。建立了原油水份传感器的数学模型，从而得到了原油含水率与原油水份传感器的等效电容之间的关系。首次把小波变换技术应用到原油含水率测试试仪中，构造的声表面波换能器的脉冲响应函数等于小波函数，从而制造出了声表面波式小波变换的重构器件，该器件可以有效滤除干扰信号。为了减小极板材料对测量的影响，极板材料可选用铁镍合金，也可选用镀有金或银的陶瓷或石英。