LPC spectrum and formant estimation
Tasks to do:
- LPC spectrum and formant estimation
For selected voiced short-time frame muz1-AA-frame.CS0
(raw data without header, fs=16000 Hz, for download into MATLAB
use loadbin.m) estimate formant frequencies in the following steps:
- compute and observe DFT-based power spectrum
- compute LPC coefficients and LPC power spectrum (parameters of AR model
compute on the basis of autocorrelation method using MATLAB
function lpc or aryule. You can use also
Burg algorthm using MATLAB function arburg.
- Observe the positions of zeros and poles of AR model transfer function.
- For related poles (p_1 and p_2) compute values of formant
frequnecies (F1 and F2), see lecture slides
- Display the values of formant frequencies vyneste into a figure and proove that they correspond to the peaks of smoothed LPC spectrum
- 1st checked result: Display for voiced frame
- waveform of the signal
- DFT and LPC spectrum
- 2nd checked result: Display for voiced frame
- the diagram of zeros and poles for computed AR model,
- formant frequencies F1 and F2 in LPC spectrum.
- Analysis of formants of basic vowels
- Compute the 1st and 2nd formant for all 5 basic vowels (F1 and
- Work with signals from the database zreratdb which is available for direct usage in CTU FEE computer rooms at the directory "H:\VYUKA\ZRE\signaly\zreratdb". For your work outside of CTU FEE, it is possible to download the archive zrerat_blocken_2018_cs0.zip which contains signals resampled to 16 kHz.
- Draw vowel formants for chosen speaker.
- 3rd checked result:
For speaker T16204 (signals are in the directory H:\VYUKA\ZRE\signaly\zreratdb\BLOCK162\T16204 or in the following archive zrerat_T16204_vowels_cs0.zip.) draw
- time dependancy of concatenated vowels a-e-i-o-u for the 1st realizations of all 5 vowels,
- time dependancy of the first 4 formants for concatenated vowels a-e-i-o-u for the 1st realizations of all 5 vowels,
- for all vowel realizations A1,A2,A3,....,U1,U2,U3 of speaker
T16204 draw formant triangle, i.e. computed values of the first and the second formats draw into
the graph F1 = f ( F2 ). Point related to each particular vowel resolve by different colour.
- Observe formant estimation in Praat
(i.e. time dependacy of formants in signal spectrogram).
- Repeat for your own records and on the basis of formant triangle for vowels pronounced by you correct the potentionally bad recordings of 5 basic vowels, i.e. remove possibly long pause at the beginning and the end of a record or rerecord possibly completely bad vowel realizations.
- 4th checked result: formant
traingle for all available short-time frames for your realizations of 5 basic vowels.
- Corrected records and whole 4th checked result respectively can be completed at home and deliver till the end of current week (i.e. till Su 23:59). Delivery can be done via Moodle, see DELIVERY seminar formants.