Programmer Guide/Command Reference/EVAL/formants

Format tracking algorithm.

Usage

formants(cf, ca, f0, mflag, bias, lmin)

cf

a matrix containing the frequencies of the formant candidates in Hz

ca

a matrix containing the amplitudes of formant candidates in dB

• each row of cf/ca contains the candidates of one frame
• number of frames: N=nrow(cf)
• maximum number of candidates M=ncol(cf)
• ca must be a matrix with the same dimensions as cf or a scalar (if amplitudes should not be used for formant tracking)

f0

f0 vector

• f0 must be a vector with length N containing the f0 values or a scalar (if f0 should not be used for formant tracking)
• if f0 is supplied, the formant tracking is only applied to voiced regions

mflag

selects the tracking method

• currently only one method (mflag=0) is implemented (see sp-atom FORMANTS for more details)
• a second method using a formant modell is under development

bias

tracking bias in Hz; This value is used to check if two candidates can be connected (|cf[i1,j1]-cf[i2,j2]) / (cf[i1,j1]+cf[i2,j2]+2*bias) must be lower than 0.1).

lmin

the minimum length of a track in frames

Result

The f0 vector. The vector contains the f0 values in Hz. The vector length depends mainly on the length of the signal vector x and the hopsize dt. For unvoiced frames the f0 values are set to zero.

See also

f0ac, lpc, cepstrum, ipeaks, FORMANTS

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