| 摘要 |
A method and an arrangement are described by means of which a pitch in a signal (s(t)) can be determined. In fact the probability density function (pdf) of the pitch is determined as a function of frequency. A pitch can then be derived from this probability density function. First a frequency spectrum A(f) is derived from a signal portion situated in a specific time interval T. Then, the probability contribution (K1i, K1j, . . . . ) is determined for a number of frequency components (fi, fj, . . . ), stating the relative probability that a pitch at a frequency (f1) is the result of a frequency component (fi, fj, . . . ). The probability contributions (K1i, K1j, . . . ) are multiplied by one another to obtain a probability density (Kf1). This procedure is iterated for successive frequencies (f2, . . . ) to obtain at least a second probability density. The probability densities Kf1, Kf2, . . . are each a measure of the relative probability that a pitch occurs at the frequencies f1, f2, . . . , respectively. The probability density function (pdf) from which one or more pitches can be derived (FIG. 4 a) can be determined from the computed probability densities (Kf1, Kf2, . . . ).
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