1. Measured Period 8 6 4 2 VOICE SIGNAL -2 -4 -6 -8 0.018 0.02 0.022
VOICE SIGNAL -2 -4 -6
Measured Period -8
0.018
0.02
0.022
0.024
0.026
0.028
0.03
0.032
0.034
0.036
TIME (SEC)
Figure Identification of negative peaks for fundamental frequency tracking on a typical original voice signal. The tracking algorithm automatically selects the minima indicated by X and performs a parabolic interpolation to determine the time of minima to a precision of less than one sample. Circles indicate sample points.

2. 275
270
FREQ (HZ)
265
260
255
0.2
0.4
0.6
0.8 1
TIME (SEC)
Figure A high resolution 1 sec. fundamental frequency track resulting from subsample interpolation. Note lack of fundamental frequency quantization (flat spots) that would occur without interpolation.

3. 275
270
FREQ (HZ)
265
260
0.2
0.4
0.6
0.8 1
TIME (SEC) 4 2
FREQ (HZ) -2 -4
0.2
0.4
0.6
0.8 1
TIME (SEC)
Figure The fundamental frequency track of Fig 2.20 is low pass filtered (top part A curve) and high pass filtered (bottom part B curve) yielding the tremor and HFPV time series respectively. A cutoff frequency of 10 Hz is selected.

4. 45 40 35 30 25
#OCCURRANCES 20 15 10 5
-1.5 -1
-0.5
0.5 1
1.5
DELT FREQ (%) TOTSKIP=0 FCUT=10 TOTMAN=0
Figure Histogram of frequency deviations of the high pass filtered fundamental frequency time series of Fig Successful fundamental frequency tracking yields a Gaussian form distribution.

5. ORIGINAL FUNDAMENTAL FREQ.
250
ORIGINAL FUNDAMENTAL FREQ.
240
RESAMPLED FUNDAMENTAL FREQ.
230
FUNDAMENTAL FREQUENCY (HZ)
220
210
200
190
0.2
0.4
0.6
0.8 1
TIME (SEC)
Figure Fundamental frequency time series of original voice and voice re-sampled to remove tremor (low frequency variations). Most of the significant fundamental frequency variation is removed

6. FREQ (Hz) TIME (SEC) DELTA FREQ PERCENT 0.2 0.4 0.6 0.8 1 266.2 266.4
0.2
0.4
0.6
0.8 1
266.2
266.4
266.6
FREQ (Hz)
TIME (SEC)
-0.1
-0.05
0.05
0.1
DELTA FREQ PERCENT
Figure Fundamental frequency time series of voice re-sampled to remove all fundamental period variations: both HFPV and tremor. In the upper plot the residual variation after removal is shown in Hz; it is less than 0.4 Hz. In the lower plot the residual is shown in percent.