Davide Cilano
Fall 1995
© IEEE Computer Society Press.


3.2.1.4.2. Tonal components

A local maximum is added to the list of tonal components if:

X(k) - X(k + j) >= 7 dB

where j is chosed in function of k as follows:

values of kvalues of j
Layer I2<k<63-2, +2
62<k<127-3, -2, +2, +3
126<k<250-6, ... , -2, +2, ... , +6
Layer II2<k<63-2, +2
62<k<127-3, -2, +2, +3
126<k<255-6, ... , -2, +2, ... , +6
254<k<500-12, ... , -2, +2, ... , +12

Values of j (index of the spectral line) within which to verify whether a component is tonal are shown above. Such values can be obtained from the distance in kHz between the frequency components and by counting the number of those components that cover the frequency intervals according to the above table.

The values j=+1 and j=-1 are not considered because they have already been used in the identification of local maxima. For each component which happens to be TONAL the following must be saved:

- index k of the spectral line
- SPL level Xtm(k) = X(k-1) + X(k) + X(k+1) in dB
- flag indicating TONAL

The other spectral lines in the examined frequency interval are set to minus infinite.


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