| lpc {phonTools} | R Documentation |
Linear Predictive Coding
Description
Predict autoregressive filter coefficients.
Usage
lpc (sound, order = round(fs/1000)+3, fs = 10000, show = FALSE,
add = FALSE, preemph = TRUE)
Arguments
sound |
Either a numeric vector representing a sequence of samples taken from a sound wave or a sound object created with the loadsound() or makesound() functions. |
order |
The number of LPC coefficients to be estimated. By default there is 2 per kHz below the Nyquist frequency plus 3 extra coefficients. |
fs |
The sampling frequency in Hz. If a sound object is passed this does not need to be specificed. |
show |
If TRUE, the frequency response of the estimated filter is plotted. |
add |
If TRUE, the frequency response plot is added to an existing plot. |
preemph |
If TRUE, preemphasis of 3 dB per octave is applied to the sound before analysis. |
Details
LPC coefficients are estimated using the autocorrelation method. The signal is windowed with a Hanning window prior to analysis.
Value
A vector containing the LPC coefficients is returned.
Author(s)
Santiago Barreda <sbarreda@ucdavis.edu>
Examples
## 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 = 100, dur = 250)
## let the LPC function estimate the filter used to generate the vowel
#coeffs = lpc (sound, show = TRUE)