Fig. 1. Signal parameter measurements. (A) EOD frequency trace (top) and head-to-tail EOD waveform (voltage) trace (bottom). (B) Power spectrum (8192 points, Hanning window) of an EOD recording showing fundamental (F1), second (F2) and third (F3) harmonic frequencies. (C) EOD frequency trace (top), head-to-tail EOD waveform (voltage) trace (middle), and root-mean-square (RMS) EOD amplitude trace (bottom) for a single chirp. Points used to measure signal parameters are indicated with crosses and/or arrows. See Table 1 for details on how duration and FM parameters were calculated from these points. (D) EOD frequency trace (top) and head-to-tail EOD waveform (voltage) trace (bottom) for a chirp with extreme and prolonged reduction of EOD amplitude. Broken red line indicates where EOD frequency was not measurable (i.e. when RMS EOD amplitude dropped below 15% of baseline). Estimates of EODf were fixed at this frequency until RMS EOD amplitude returned to at least 15% of its baseline.