Method and apparatus for time based measurement of impedance

Claim 1

System for automatic time-based measurement of impedance in an electrical unknown component, comprising: (a) generating circuit means for generating a sine wave signal of desired measurement frequency, (b) measurement circuit means containing an unknown impedance component and also including reference resistance means in series with said unknown component across which said sine wave signal is simultaneously applied, (c) comparator circuit means for receiving the signals applied across the unknown component and across the reference resistance means, said signals being amplified to said comparator circuit means such that they are not subjected to phase sensitive detection nor to analog-to-digital conversion, said comparator circuit means also including reference voltage circuit input means for establishing a reference voltage level and further including polarity reversing circuit input means so that sine wave signals applied to said reference resistance means and said unknown component cross and recross in positive going and negative going transistions the defined reference voltage level to produce detectable and measureable time defined signals, (d) timing circuit means for receiving signals from said generating circuit means in order to initiate four timing cycles at the same point in time, two each of which said four cycle measure lapses of time with respect to transitions of said sine wave signal across said reference voltage level for each of said unknown component and said reference resistance means to thereby enable calculations by a processor means of impedance based on said timing cycles, and to receive time defined signals from said comparator circuit means, and (e) processor means for reading said time lapses and for calculating impedance in said unknown component.