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e0df82056c
Updated CAPS plugins to version 0.4.3 - changes: * basics.h cleanup / comments * minor Makefile cleanup * comment cosmetics * Eq and Eq2x2 per-band Q changed to 1.414 (= 1 octave) * Eq lowest band default value fixed to read 0 * Niclas' fix for the bessel function implemented * uninitialised plugin states eliminated thanks to Damon * linker options for OSX added to the Makefile Signed-off-by: Tobias Doerffel <tobias.doerffel@gmail.com>
163 lines
2.6 KiB
C++
163 lines
2.6 KiB
C++
/*
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dsp/BiQuad.h
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Copyright 2003-7 Tim Goetze <tim@quitte.de>
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http://quitte.de/dsp/
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Bi-quad IIR filter.
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*/
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/*
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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02111-1307, USA or point your web browser to http://www.gnu.org.
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*/
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#ifndef _DSP_BI_QUAD_H_
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#define _DSP_BI_QUAD_H_
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namespace DSP {
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class BiQuad
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{
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public:
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/* coefficients */
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d_sample a[3], b[3];
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/* history */
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int h;
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d_sample x[2], y[2];
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BiQuad()
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{
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/* initialize to unity */
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a[0] = 1;
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a[1] = a[2] = b[0] = b[1] = b[2] = 0;
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reset();
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}
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void copy (BiQuad & bq)
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{
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for (int i = 0; i < 3; ++i)
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a[i] = bq.a[i],
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b[i] = bq.b[i];
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}
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void reset()
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{
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h = 0;
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x[0] = x[1] =
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y[0] = y[1] = 0.;
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}
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/* denormal zapping */
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void flush_0()
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{
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for (int i = 0; i < 2; ++i)
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if (is_denormal (y[i]))
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y[i] = 0;
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}
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inline d_sample process (d_sample s)
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{
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register int z = h;
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register d_sample r = s * a[0];
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r += a[1] * x[z];
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r += b[1] * y[z];
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z ^= 1;
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r += a[2] * x[z];
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r += b[2] * y[z];
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y[z] = r;
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x[z] = s;
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h = z;
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return r;
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}
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/* Following are additional methods for using the biquad to filter an
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* upsampled signal with 0 padding -- some terms reduce to 0 in this
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* case */
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inline d_sample process_0_1()
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{
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register int z = h;
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register d_sample r = 0;
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r += a[1] * x[z];
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r += b[1] * y[z];
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z ^= 1;
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r += a[2] * x[z];
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r += b[2] * y[z];
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y[z] = r;
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x[z] = 0;
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h = z;
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return r;
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}
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inline d_sample process_0_2()
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{
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register int z = h;
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register d_sample r = 0;
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r += b[1] * y[z];
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z ^= 1;
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r += a[2] * x[z];
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r += b[2] * y[z];
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y[z] = r;
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x[z] = 0;
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h = z;
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return r;
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}
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inline d_sample process_0_3()
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{
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register int z = h;
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register d_sample r = 0;
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r += b[1] * y[z];
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z ^= 1;
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r += b[2] * y[z];
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y[z] = r;
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x[z] = 0;
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h = z;
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return r;
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}
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};
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} /* namespace DSP */
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#endif /* _DSP_BI_QUAD_H_ */
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