Digital eddy current proximity system: apparatus and method

A method for measuring a gap between a proximity probe and a conductive target material, said method including the steps of:

• providing a network of components including a first electrical component, an extension cable component and a proximity probe component respectively serially connected, and locating the proximity probe adjacent a conductive target material;
• driving a dynamic current through the serially connected electrical components for impressing a first analog voltage across the network and a second analog voltage across the serial connection of the extension cable component and the proximity probe component;
• sampling and digitizing the first analog voltage impressed across said network to obtain a first digitized voltage value;
• sampling and digitizing a second analog voltage impressed across the serial connection of the extension cable component and the proximity probe component to obtain a second digitized voltage value;
• digitally convolving the first digitized voltage value and the second digitized voltage value into a first complex number and a second complex number respectively;
• calculating a voltage ratio of the second complex number to a difference between the first complex number and the second complex number;
• processing the voltage ratio into a gap value correlative to a gap between the proximity probe and the conductive target material.