autoExcitation Spectrum_to_Excitation (Spectrum me, double dbark) {
try {
long nbark = (int) floor (25.6 / dbark + 0.5);
double *re = my z [1], *im = my z [2];
autoNUMvector <double> auditoryFilter (1, nbark);
double filterArea = 0;
for (long i = 1; i <= nbark; i ++) {
double bark = dbark * (i - nbark/2) + 0.474;
filterArea += auditoryFilter [i] = pow (10, (1.581 + 0.75 * bark - 1.75 * sqrt (1 + bark * bark)));
}
/*for (long i = 1; i <= nbark; i ++)
auditoryFilter [i] /= filterArea;*/
autoNUMvector <double> rFreqs (1, nbark + 1);
autoNUMvector <long> iFreqs (1, nbark + 1);
for (long i = 1; i <= nbark + 1; i ++) {
rFreqs [i] = Excitation_barkToHertz (dbark * (i - 1));
iFreqs [i] = Sampled_xToNearestIndex (me, rFreqs [i]);
}
autoNUMvector <double> inSig (1, nbark);
for (long i = 1; i <= nbark; i ++) {
long low = iFreqs [i], high = iFreqs [i + 1] - 1;
if (low < 1) low = 1;
if (high > my nx) high = my nx;
for (long j = low; j <= high; j ++) {
inSig [i] += re [j] * re [j] + im [j] * im [j]; // Pa2 s2
}
/* An anti-undersampling correction. */
if (high >= low)
inSig [i] *= 2.0 * (rFreqs [i + 1] - rFreqs [i]) / (high - low + 1) * my dx; // Pa2: power density in this band
}
/* Convolution with auditory (masking) filter. */
autoNUMvector <double> outSig (1, 2 * nbark);
for (long i = 1; i <= nbark; i ++) {
for (long j = 1; j <= nbark; j ++) {
outSig [i + j] += inSig [i] * auditoryFilter [j];
}
}
autoExcitation thee = Excitation_create (dbark, nbark);
for (long i = 1; i <= nbark; i ++) {
thy z [1] [i] = Excitation_soundPressureToPhon (sqrt (outSig [i + nbark/2]), Sampled_indexToX (thee.get(), i));
}
return thee;
} catch (MelderError) {
Melder_throw (me, U": not converted to Excitation.");
}
}
Any Cochleagram_to_Excitation (I, double t)
{
iam (Cochleagram);
long column = Matrix_xToNearestColumn (me, t), ifreq;
Excitation thee;
if (column < 1) column = 1;
if (column > my nx) column = my nx;
thee = Excitation_create (my dy, my ny);
if (! thee) return NULL;
for (ifreq = 1; ifreq <= my ny; ifreq ++)
thy z [1] [ifreq] = my z [ifreq] [column];
return thee;
}
autoExcitation Cochleagram_to_Excitation (Cochleagram me, double t) {
try {
long column = Matrix_xToNearestColumn (me, t);
if (column < 1) column = 1;
if (column > my nx) column = my nx;
autoExcitation thee = Excitation_create (my dy, my ny);
for (long ifreq = 1; ifreq <= my ny; ifreq ++)
thy z [1] [ifreq] = my z [ifreq] [column];
return thee;
} catch (MelderError) {
Melder_throw (me, U": slice at time ", t, U" seconds not extracted to Excitation.");
}
}
