Santiago Barreda
Assistant Professor, Department of Linguistics, UC Davis

Main Research Vignettes CV phonTools Statistics Links


lpc [phonTools] 

Linear predictive coding (autocorrelation) estimation of filter coefficients. These coefficients can be used to estimate formants, estimate spectral envelope, or filter, or inverse-filter different signals. In the example below, a synthetic vowel with known formants was created, and this function was used to estimate the spectral envelope of the vowel.




Code used to generate examples:

par (mar = c(4,4,1,1)) ## make a synthetic vowel with a known set of formant frequencies sound = vowelsynth (ffs = c(500,1500,2500,3500,4500), fbw = c(30, 80, 150, 200, 220),f0 = 150, dur = 250) ## let the LPC function estimate the filter used to generate the vowel coeffs = lpc (sound, show = TRUE) ## and compare to specified formant frequencies spectralslice (sound, ylim = c(-45, 5), col=4, preemphasisf = 50) freqresponse (1, coeffs, fs=10000, add = TRUE) abline (v = c(500,1500,2500,3500,4500), col = 2, lwd=1, lty =2)