Patent ID: 7949499

Claim:
Metering apparatus including signal filtering to remove or reduce random noise from a signal or signals of interest, comprising: at least one sensor for providing at least one initial signal output; solid state circuitry for receiving said at least one initial signal output of said at least one sensor, synchronously sampling said at least one initial signal output at different respective points of a predetermined number of consecutive periodic signal cycles thereof such that the frequency of said respective points per cycle is a constant integer multiple of the frequency of the at least one initial signal output, summing such respective point samples to produce a composite signal, said composite signal comprising sample points corresponding in value to summed values of matching respective point samples of said predetermined number of consecutive periodic signal cycles, and averaging said sample points of said composite signal based at least in part on said predetermined number of consecutive periodic signal cycles; wherein said solid state circuitry is operative so that said predetermined number of consecutive cycles sampled increases with a decrease in signal amplitude of said at least one initial signal output.