Method for digitally measuring electrical impedance

DETAILED DESCRIPTION The instant invention is distinguished over the known prior art in a multiplicity of ways.
For one thing, the instant invention provides a unique digital system for digitally measuring an unknown electrical impedance.
Additionally, the instant invention provides a digital proximity system that is a direct one for one replacement for existing analog eddy current proximity systems which is compatible with any existing (or future) eddy current proximity probe (a noncontacting device which measures displacement motion and position of an observed conductive or metallic target material relative to the probe) and extension cable assembly.
Thus, the instant invention can directly replace the analog conditioning circuitry of prior art analog systems thereby eliminating the anomalies associated with manufacturing and component variations, and tolerances of these systems.
Furthermore, the instant invention eliminates the laborious design and calibration methods required to calibrate prior art analog systems in order to compensate for manufacturing and component variations, tolerances and environmental conditions.
In one form, the instant invention provides a system which includes a unique voltage ratio apparatus and method for digitally measuring an unknown electrical component value.
The system accomplishes this by digitizing a first voltage impressed across a serial coupling of a first electrical component and a second electrical component, and by digitizing a second voltage impressed across the second electrical component only.
Each of the two digitized voltages is then convolved with digitized waveforms to obtain a first and a second complex voltage number.
A ratio of the second complex number to a difference between the first and the second complex number is determined and multiplied by a known value of the first electrical component to determine the unknown value of the second electrical component.
A resistance means having a known value can be employed as the first electrical component