Geobandwidth: comparing EM waveforms with a wire-loop model

We compare time domain systems of different waveform shape, power and receiver sampling times using a wire-loop conductor model to define a comprehensive “geobandwidth” that shows the strength of the response over a range of decay constants, analogous to a range of conductance. Frequency domain EM responses can also be calculated as a function of decay constant for a wire loop model, giving a consistent comparison method for all time domain waveforms and frequency domain. Peak decay constant or equivalent frequency can be determined analytically or numerically. Arbitrary waveforms can be modelled as a sum of simple short ramps, and the geobandwidth determined numerically. The frequency content of a time-domain system can be defined by the peak decay constant or the equivalent frequency. The results compare response amplitude across the full range of geological target conductance. Systems can be compared on the basis of signal or signal/noise ratio.