2024-07-17 19:50:58 +00:00
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/* resample.c
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This file is part of a program that implements a Software-Defined Radio.
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Copyright (C) 2013 Warren Pratt, NR0V
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Copyright (C) 2024 Edouard Griffiths, F4EXB Adapted to SDRangel
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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The author can be reached by email at
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warren@wpratt.com
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*/
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#include "comm.hpp"
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#include "fir.hpp"
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#include "resamplef.hpp"
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namespace WDSP {
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/************************************************************************************************
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* *
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* VERSION FOR NON-COMPLEX FLOATS *
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* *
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************************************************************************************************/
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RESAMPLEF* RESAMPLEF::create_resampleF ( int run, int size, float* in, float* out, int in_rate, int out_rate)
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{
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RESAMPLEF *a = new RESAMPLEF;
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int x, y, z;
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int i, j, k;
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int min_rate;
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float full_rate;
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float fc;
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float fc_norm;
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float* impulse;
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a->run = run;
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a->size = size;
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a->in = in;
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a->out = out;
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x = in_rate;
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y = out_rate;
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while (y != 0)
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{
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z = y;
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y = x % y;
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x = z;
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}
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a->L = out_rate / x;
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a->M = in_rate / x;
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2024-07-21 12:20:48 +00:00
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a->L = a->L <= 0 ? 1 : a->L;
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a->M = a->M <= 0 ? 1 : a->M;
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2024-07-19 06:10:54 +00:00
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2024-07-17 19:50:58 +00:00
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if (in_rate < out_rate)
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min_rate = in_rate;
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else
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min_rate = out_rate;
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fc = 0.45 * (float)min_rate;
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full_rate = (float)(in_rate * a->L);
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fc_norm = fc / full_rate;
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a->ncoef = (int)(60.0 / fc_norm);
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a->ncoef = (a->ncoef / a->L + 1) * a->L;
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a->cpp = a->ncoef / a->L;
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a->h = new float[a->ncoef]; // (float *) malloc0 (a->ncoef * sizeof (float));
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impulse = FIR::fir_bandpass (a->ncoef, -fc_norm, +fc_norm, 1.0, 1, 0, (float)a->L);
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i = 0;
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for (j = 0; j < a->L; j ++)
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{
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for (k = 0; k < a->ncoef; k += a->L)
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a->h[i++] = impulse[j + k];
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}
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a->ringsize = a->cpp;
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a->ring = new float[a->ringsize]; //(float *) malloc0 (a->ringsize * sizeof (float));
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a->idx_in = a->ringsize - 1;
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a->phnum = 0;
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delete[] (impulse);
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return a;
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}
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void RESAMPLEF::destroy_resampleF (RESAMPLEF *a)
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{
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delete[] (a->ring);
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delete[] (a->h);
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delete (a);
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}
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void RESAMPLEF::flush_resampleF (RESAMPLEF *a)
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{
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memset (a->ring, 0, a->ringsize * sizeof (float));
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a->idx_in = a->ringsize - 1;
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a->phnum = 0;
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}
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int RESAMPLEF::xresampleF (RESAMPLEF *a)
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{
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int outsamps = 0;
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if (a->run)
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{
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int i, j, n;
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int idx_out;
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float I;
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for (i = 0; i < a->size; i++)
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{
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a->ring[a->idx_in] = (float)a->in[i];
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while (a->phnum < a->L)
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{
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I = 0.0;
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n = a->cpp * a->phnum;
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for (j = 0; j < a->cpp; j++)
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{
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if ((idx_out = a->idx_in + j) >= a->ringsize)
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idx_out -= a->ringsize;
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I += a->h[n + j] * a->ring[idx_out];
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}
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a->out[outsamps] = (float)I;
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outsamps++;
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a->phnum += a->M;
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}
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a->phnum -= a->L;
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if (--a->idx_in < 0)
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a->idx_in = a->ringsize - 1;
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}
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}
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else if (a->in != a->out)
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{
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memcpy (a->out, a->in, a->size * sizeof (float));
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}
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return outsamps;
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}
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// Exported calls
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void* RESAMPLEF::create_resampleFV (int in_rate, int out_rate)
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{
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return (void *) create_resampleF (1, 0, 0, 0, in_rate, out_rate);
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}
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void RESAMPLEF::xresampleFV (float* input, float* output, int numsamps, int* outsamps, void* ptr)
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{
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RESAMPLEF *a = (RESAMPLEF*) ptr;
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a->in = input;
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a->out = output;
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a->size = numsamps;
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*outsamps = xresampleF(a);
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}
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void RESAMPLEF::destroy_resampleFV (void* ptr)
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{
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destroy_resampleF ( (RESAMPLEF*) ptr );
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}
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} // namespace WDSP
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