#$%^&*AU2017204821A120180201.pdf#####ABSTRACT A method described herein includes describing a load current with a discrete time function. The method includes using a first frequency and a second frequency to provide an approximation of the described load current, wherein a transform applied to the discrete time function identifies the first frequency and the second frequency. The method includes estimating a loop inductance and a loop resistance of a wire loop by exciting a transmit circuit with a voltage reference step waveform, wherein the transmit circuit includes the wire loop. The method includes scaling the approximated load current to a level sufficient to generate a minimum receive voltage signal in a receiver at a first distance between the wire loop and the receiver. The method includes generating a first voltage signal using the scaled load current, estimated loop inductance, and estimated loop resistance. The method includes exciting the transmit circuit with the first voltage signal.1/21 100 Transmit 104 112 -- - - - -- Rers Data + Polarity i iL(t) 102 Generator Amliie T out(t) L16 LLoop VREF I I Load VREF I108 118b 114 Loop 120 ADC 12+ channel 1 0 VC (t 11 Rgense 120 ADC channel 2 FIG IVreturn 12
