/usr/include/mffm/fastDepukfb.H is in libaudiomask-dev 1.0-3.
This file is owned by root:root, with mode 0o644.
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libaudiomask - hybrid simultaneous audio masking threshold evaluation library
Copyright (C) 2000-2010 Dr Matthew Raphael Flax
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef FASTDEPUKFB_H_
#define FASTDEPUKFB_H_
#include <string.h>
#include "depukfb.H"
class FastDepUKFB : public DepUKFB {
double n_l[2], d_l[3]; // Lower filter IIR coeff.
double n_u[2], d_u[3]; // Upper filter IIR coeff.
void findIIRCoeff(double fc, double pl, double pu){
double c1, c2, c3, c4; // Numerator coefficients
double d1, d2, d3, d4; // Denominator coefficients
// Find the lower filter's IIR coefficients first
c1=exp(pl/fc);
c2=exp(pl);
//c5=c1*c1;
c4=c1*c2;
c3=c1*c4;
d_l[0]=(c2*fc); // Do this first so we can divide by it
n_l[0]=(fc+fc*pl)/d_l[0]; // Numerator
n_l[1]=(-c1*fc-c1*pl-c1*fc*pl)/d_l[0];
d_l[1]=(-2*c4*fc)/d_l[0]; // Denominator
d_l[2]=(c3*fc)/d_l[0];
d_l[0]=1.0;
// Find the upper filter's IIR coefficients
d4=exp(pu/fc);
d3=d4*d4;
d2=exp(pu+pu/fc);
d1=d2*d4;
d_u[0]=(d3*fc);
n_u[0]=(d1*fc-d1*fc*pu)/d_u[0]; // Numerator
n_u[1]=d2*(-fc+pu+pu*fc)/d_u[0];
d_u[1]=(-2*d4*fc)/d_u[0]; // Denominator
d_u[2]=(fc)/d_u[0];
d_u[0]=1.0;
}
void filter(double fc, double *out){
//Second order impulse response
// Reset the state vars and the output
double z1=0.0, z2=0.0;
bzero(out, (int)rint(fs/2.0)*sizeof(double));
// Upper filter ...
// First excite with a unit input ....
out[0] = n_u[0] - d_u[0]*out[0] + z1;
z1 = n_u[1] - d_u[1]*out[0] + z2;
z2 = - d_u[2]*out[0];
for (int i=1;i<(int)rint(fs/2.0);i++){ // the input now equals zero
out[i] = - d_u[0]*out[i] + z1;
z1 = - d_u[1]*out[i] + z2;
z2 = - d_u[2]*out[i];
}
// Reset the state vars and the lower output
z1=z2=0.0;
bzero(out, (int)rint(fc)*sizeof(double));
// Lower filter ...
// First excite with a unit input ....
out[0] = n_l[0] - d_l[0]*out[0] + z1;
z1 = n_l[1] - d_l[1]*out[0] + z2;
z2 = - d_l[2]*out[0];
for (int i=1;i<(int)rint(fc);i++){ // the input now equals zero
out[i] = - d_l[0]*out[i] + z1;
z1 = - d_l[1]*out[i] + z2;
z2 = - d_l[2]*out[i];
}
}
void afZ(double fc, int whichFilter, double pl, double pu){
double *filt=w[whichFilter];
findIIRCoeff(fc, pl, pu); // Find the IIR coefficients to filter with
filter(fc, filt); // Find the lower filter shape
}
/// Auditory Filter procedure
virtual void af(double fc, int whichFilter){
cout<<"FastDepUKFB::af"<<endl;
// Produce the filter
afZ(fc, whichFilter, p_l(fc), p_u(fc));
}
public:
FastDepUKFB(int sampleFreq, int fCnt=50) {
init(sampleFreq, fCnt);
}
};
#endif //FASTDEPUKFB_H_
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