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1. Harmonics (specially those emphasízed by formants) preferred to (true?) pitch (included in  An_aadf_pitch_estimator).

A simple rule differentiates (true) pitch of its harmonic-formants (explain): they move less in time, are more stable, because they change with the timbre of the vowel or consonants meanwhile fundamental and sub harmonics (multiples of the true periods, don't.

In the picture can be seen the ADA function for the speech signal, down in the window. We see how for each major lobe in the signal we find another in the ADA. In this case they are less important than the peaks related to the true pitch (right) and its first sub-harmonic (left). Besides that , the true pitch have been preferred because it is higher than the others.

In the second figure, the three peaks (true pitch, low octave and first harmonic-format, the octave are almost equal: and indeed, the signal is almost periodic with half the true period in this precise moment, on the signal peak. The decision is still correct, because the true peak is higher in the third octave, without the high emphasis octaves5s a‒35ed t6 the former, now the sub harmonic have wrongly preferred (?)

In the fourth figure, the emphasis for high pitches, the lower fundamental, and the strong fist harmonics have cause s the decision to be wrong, taking the third harmonic as fundamental.


So other considerations than the relative height of the peaks in ADA must be taken in consideration.






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