### ASA 124th Meeting New Orleans 1992 October

## 4pMU2. Fundamental frequency tracking in the log frequency domain based on
a pattern recognition algorithm.

**Judith C. Brown
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*Media Lab., MIT, Cambridge, MA 02139
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Wellesley College, Wellesley, MA 02181
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**Miller S. Puckette
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*IRCAM, Paris 75004, France
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When the Fourier components of a sound with harmonic frequency components
are plotted against log frequency, a constant pattern independent of
fundamental frequency is obtained. A computationally efficient implementation
[J. C. Brown and M. S. Puckette, ``An efficient algorithm for the calculation
of a constant Q transform,'' J. Acoust. Soc. Am. (to be published 1992)] will
be described. One can then calculate the cross-correlation function of these
spectra with the ideal pattern, which consists of ones at the positions of the
harmonic frequency components, to obtain the fundamental frequency of the input
signal. Extremely accurate values of the fundamental frequency can be obtained
using a method based on phase changes of the discrete Fourier transform [J. C.
Brown and M. S. Puckette, ``A high resolution fundamental frequency
determination based on phase changes of the Fourier transform,'' submitted to
J. Acoust. Soc. Am. (1992)]. Results for a variety of musical instruments will
be presented, including recent results on tracking very low frequencies
produced by a cello.