Fig. 6. (A–D) An anomalous pulse from the song of the same Gryllus campestris as in Fig. 3. (A) Oscillogram of a single pulse of a chirp of the song. (B) An oscillogram of the pulse shown in A after filtering to remove frequencies below 7.5 kHz; this waveform has been amplified 16-fold relative to that shown in A. (C) Plot of the cycle-by-cycle frequencies of the broad-band waveform shown in A (filled circles) and the without-FD (the song pulse after filtering out the peak at the dominant frequency FD of the song pulse) waveform shown in B (open circles); the frequency scale for the broad-band waveform is on the left and that for the without-FD waveform is on the right. A, B and C use the same time scale; the asterisks show the regions at which the waveforms and frequency became irregular. (D) A 2.5 ms section of the waveforms shown in A and B from the region around the irregularities in the waveforms. The thick line shows the broad-band waveform and the thin line shows the without-FD waveform amplified 16-fold relative to the broad-band waveform. The time scale in D shows the regions of the pulse that have been amplified, the vertical dashed lines show the relative phasing of the broad-band and without-FD waveforms and the asterisks shows the region of the pulse in which the without-FD waveform became small in amplitude. This was preceded by an irregularity in the broad-band waveform and an increase in amplitude of the without-FD waveform (horizontal dashed lines). (E) Plot of the cycle-by-cycle frequencies of the broad-band waveforms of five pulses that show similar pulse envelopes to that shown in A. The anomaly appears at the same place in each pulse, shown by an asterisk which corresponds with the asterisk in A and B.
