Patent ID: 7746057

Claim:
A power measurement system comprising: a current measurement circuit for measuring a current through a load; a first bandpass filter having a bandpass filter response formed by two or more filter stages each having a single complex pole, wherein the poles of each of the stages have a frequency relationship in the complex plane other than a conjugate frequency relationship, wherein the first bandpass filter has an input coupled to an output of the current measurement circuit and provides complex current output components having a substantially quadrature phase relationship throughout a pass-band of the first bandpass filter, and wherein the first bandpass filter response rejects one of a positive or a negative half of a complex frequency spectrum; a voltage measurement circuit for measuring a voltage across terminals of the load; a second bandpass filter having a response substantially identical to the bandpass filter response, wherein the second bandpass filter has an input coupled to an output of the voltage measurement circuit and provides complex voltage output components having a substantially quadrature phase relationship throughout a pass-band of the second bandpass filter; and a processing system for receiving the complex current output components and the complex voltage output components and providing at least one indication of a power provided to the load.