Spectrogram from Scientific Research

Pitfalls and specialized opportunities for formant tracking in high-pitched vocalizations. The formant structure is virtually invisible in the tonal part of this modulated high-pitched call, apart from slight changes in amplitude as f o crosses the first formant (yellow circles). Nonlinear phenomena (see Table 1 ) may help to reveal formant frequencies (here, true formants, labeled F 1 to F 4, are visible in the chaos), but caution is needed to avoid confusing formants with sidebands (resulting from modulation) or residual harmonics

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