inductively coupled loops a common subject in many electromagnetic textbooks in such analyses an extended conductor is treated as a circuit having resistance and inductance just as transmitter and receiver coils or loops do the equivalent lumped parameter circuit of the extended conductor considered here includes resistance and inductance in series the corner or characteristic frequency a point in the frequency domain where resistance is equal to inductive reactance is by convenience labeled f p as we will show f p completely characterizes the interference of diamagnetic and paramagnetic extended conductors generally f p is unknown but it can be solved along with the 6 coordinates of position and orientation in a single concurrent algorithm once known f p determines a compensation factor which used in conjunction with the imaginary part of the signal corrects for eddy current effects and improves p amp o accuracy there are 9 coupling terms for a three element transmitter and a three element receiver the coupling terms or mutual inductances are measured by dividing each of the received voltages by the time derivative of each transmitter current frequency division multiplexed trackers require fourier transform technology to separate the frequency components in the three received voltages algorithms for solving the p amp o coordinates are taught in u s pat nos 4 737 794 and 5 307 072 the entire content of both being incorporated herein by reference what follows is an analysis of.