2024-06-16 09:31:13 +00:00
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/* fir.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, 2016, 2022 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@pratt.one
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*/
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#define _CRT_SECURE_NO_WARNINGS
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2024-07-17 01:04:47 +00:00
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#include <limits>
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2024-06-16 09:31:13 +00:00
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#include "fftw3.h"
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#include "comm.hpp"
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#include "fir.hpp"
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namespace WDSP {
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2024-06-25 01:50:48 +00:00
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float* FIR::fftcv_mults (int NM, float* c_impulse)
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2024-06-16 09:31:13 +00:00
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{
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2024-07-16 21:15:13 +00:00
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float* mults = new float[NM * 2];
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float* cfft_impulse = new float[NM * 2];
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2024-07-16 23:58:47 +00:00
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fftwf_plan ptmp = fftwf_plan_dft_1d(
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NM,
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(fftwf_complex *) cfft_impulse,
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(fftwf_complex *) mults,
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FFTW_FORWARD,
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FFTW_PATIENT
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);
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2024-07-16 21:15:13 +00:00
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std::fill(cfft_impulse, cfft_impulse + NM * 2, 0);
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2024-06-16 09:31:13 +00:00
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// store complex coefs right-justified in the buffer
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2024-07-16 21:15:13 +00:00
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std::copy(c_impulse, c_impulse + (NM / 2 + 1) * 2, &(cfft_impulse[NM - 2]));
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2024-06-25 01:50:48 +00:00
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fftwf_execute (ptmp);
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fftwf_destroy_plan (ptmp);
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2024-06-16 09:31:13 +00:00
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delete[] cfft_impulse;
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return mults;
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}
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2024-06-25 01:50:48 +00:00
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float* FIR::get_fsamp_window(int N, int wintype)
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2024-06-16 09:31:13 +00:00
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{
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int i;
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2024-07-17 01:04:47 +00:00
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double arg0, arg1;
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2024-06-25 01:50:48 +00:00
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float* window = new float[N]; // (float *) malloc0 (N * sizeof(float));
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2024-06-16 09:31:13 +00:00
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switch (wintype)
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{
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case 0:
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2024-07-17 01:04:47 +00:00
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arg0 = 2.0 * PI / ((double)N - 1.0);
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2024-06-16 09:31:13 +00:00
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for (i = 0; i < N; i++)
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{
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2024-07-17 01:04:47 +00:00
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arg1 = cos(arg0 * (double)i);
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2024-06-16 09:31:13 +00:00
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window[i] = +0.21747
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+ arg1 * (-0.45325
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+ arg1 * (+0.28256
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+ arg1 * (-0.04672)));
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}
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break;
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case 1:
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2024-07-17 01:04:47 +00:00
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arg0 = 2.0 * PI / ((double)N - 1.0);
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2024-06-16 09:31:13 +00:00
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for (i = 0; i < N; ++i)
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{
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2024-07-17 01:04:47 +00:00
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arg1 = cos(arg0 * (double)i);
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2024-06-16 09:31:13 +00:00
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window[i] = +6.3964424114390378e-02
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+ arg1 * (-2.3993864599352804e-01
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+ arg1 * (+3.5015956323820469e-01
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+ arg1 * (-2.4774111897080783e-01
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+ arg1 * (+8.5438256055858031e-02
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+ arg1 * (-1.2320203369293225e-02
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+ arg1 * (+4.3778825791773474e-04))))));
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}
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break;
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default:
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for (i = 0; i < N; i++)
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window[i] = 1.0;
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}
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return window;
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}
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2024-07-17 01:04:47 +00:00
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float* FIR::fir_fsamp_odd (int N, float* A, int rtype, double scale, int wintype)
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2024-06-16 09:31:13 +00:00
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{
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int i, j;
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int mid = (N - 1) / 2;
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2024-07-17 01:04:47 +00:00
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double mag, phs;
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2024-06-25 01:50:48 +00:00
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float* window;
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2024-07-16 21:15:13 +00:00
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float *fcoef = new float[N * 2];
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float *c_impulse = new float[N * 2];
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2024-07-16 23:58:47 +00:00
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fftwf_plan ptmp = fftwf_plan_dft_1d(
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N,
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(fftwf_complex *)fcoef,
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(fftwf_complex *)c_impulse,
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FFTW_BACKWARD,
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FFTW_PATIENT
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);
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2024-07-17 01:04:47 +00:00
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double local_scale = 1.0 / (double) N;
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2024-06-16 09:31:13 +00:00
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for (i = 0; i <= mid; i++)
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{
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mag = A[i] * local_scale;
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2024-07-17 01:04:47 +00:00
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phs = - (double)mid * TWOPI * (double)i / (double)N;
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2024-06-16 09:31:13 +00:00
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fcoef[2 * i + 0] = mag * cos (phs);
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fcoef[2 * i + 1] = mag * sin (phs);
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}
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for (i = mid + 1, j = 0; i < N; i++, j++)
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{
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fcoef[2 * i + 0] = + fcoef[2 * (mid - j) + 0];
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fcoef[2 * i + 1] = - fcoef[2 * (mid - j) + 1];
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}
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2024-06-25 01:50:48 +00:00
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fftwf_execute (ptmp);
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fftwf_destroy_plan (ptmp);
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2024-06-16 09:31:13 +00:00
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delete[] fcoef;
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window = get_fsamp_window(N, wintype);
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switch (rtype)
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{
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case 0:
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for (i = 0; i < N; i++)
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c_impulse[i] = scale * c_impulse[2 * i] * window[i];
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break;
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case 1:
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for (i = 0; i < N; i++)
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{
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c_impulse[2 * i + 0] *= scale * window[i];
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c_impulse[2 * i + 1] = 0.0;
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}
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break;
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}
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delete[] window;
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return c_impulse;
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}
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2024-07-17 01:04:47 +00:00
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float* FIR::fir_fsamp (int N, float* A, int rtype, double scale, int wintype)
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2024-06-16 09:31:13 +00:00
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{
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int n, i, j, k;
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2024-07-17 01:04:47 +00:00
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double sum;
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2024-06-25 01:50:48 +00:00
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float* window;
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float *c_impulse = new float[N * 2]; // (float *) malloc0 (N * sizeof (complex));
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2024-06-16 09:31:13 +00:00
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if (N & 1)
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{
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int M = (N - 1) / 2;
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for (n = 0; n < M + 1; n++)
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{
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sum = 0.0;
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for (k = 1; k < M + 1; k++)
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sum += 2.0 * A[k] * cos(TWOPI * (n - M) * k / N);
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c_impulse[2 * n + 0] = (1.0 / N) * (A[0] + sum);
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c_impulse[2 * n + 1] = 0.0;
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}
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for (n = M + 1, j = 1; n < N; n++, j++)
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{
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c_impulse[2 * n + 0] = c_impulse[2 * (M - j) + 0];
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c_impulse[2 * n + 1] = 0.0;
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}
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}
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else
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{
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2024-07-17 01:04:47 +00:00
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double M = (double)(N - 1) / 2.0;
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2024-06-16 09:31:13 +00:00
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for (n = 0; n < N / 2; n++)
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{
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sum = 0.0;
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for (k = 1; k < N / 2; k++)
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sum += 2.0 * A[k] * cos(TWOPI * (n - M) * k / N);
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c_impulse[2 * n + 0] = (1.0 / N) * (A[0] + sum);
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c_impulse[2 * n + 1] = 0.0;
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}
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for (n = N / 2, j = 1; n < N; n++, j++)
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{
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c_impulse[2 * n + 0] = c_impulse[2 * (N / 2 - j) + 0];
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c_impulse[2 * n + 1] = 0.0;
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}
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}
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window = get_fsamp_window (N, wintype);
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switch (rtype)
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{
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case 0:
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for (i = 0; i < N; i++)
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c_impulse[i] = scale * c_impulse[2 * i] * window[i];
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break;
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case 1:
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for (i = 0; i < N; i++)
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{
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c_impulse[2 * i + 0] *= scale * window[i];
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c_impulse[2 * i + 1] = 0.0;
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}
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break;
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}
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delete[] window;
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return c_impulse;
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}
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2024-07-17 01:04:47 +00:00
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float* FIR::fir_bandpass (int N, double f_low, double f_high, double samplerate, int wintype, int rtype, double scale)
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2024-06-16 09:31:13 +00:00
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{
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2024-06-25 01:50:48 +00:00
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float *c_impulse = new float[N * 2]; // (float *) malloc0 (N * sizeof (complex));
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2024-07-17 01:04:47 +00:00
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double ft = (f_high - f_low) / (2.0 * samplerate);
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double ft_rad = TWOPI * ft;
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double w_osc = PI * (f_high + f_low) / samplerate;
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2024-06-16 09:31:13 +00:00
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int i, j;
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2024-07-17 01:04:47 +00:00
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double m = 0.5 * (double)(N - 1);
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double delta = PI / m;
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double cosphi;
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double posi, posj;
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double sinc, window, coef;
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2024-06-16 09:31:13 +00:00
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if (N & 1)
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{
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switch (rtype)
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{
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case 0:
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c_impulse[N >> 1] = scale * 2.0 * ft;
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break;
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case 1:
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c_impulse[N - 1] = scale * 2.0 * ft;
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c_impulse[ N ] = 0.0;
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break;
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}
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}
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for (i = (N + 1) / 2, j = N / 2 - 1; i < N; i++, j--)
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{
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2024-07-17 01:04:47 +00:00
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posi = (double)i - m;
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posj = (double)j - m;
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2024-06-16 09:31:13 +00:00
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sinc = sin (ft_rad * posi) / (PI * posi);
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switch (wintype)
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{
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case 0: // Blackman-Harris 4-term
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cosphi = cos (delta * i);
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window = + 0.21747
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+ cosphi * ( - 0.45325
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+ cosphi * ( + 0.28256
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+ cosphi * ( - 0.04672 )));
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break;
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case 1: // Blackman-Harris 7-term
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cosphi = cos (delta * i);
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window = + 6.3964424114390378e-02
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+ cosphi * ( - 2.3993864599352804e-01
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+ cosphi * ( + 3.5015956323820469e-01
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+ cosphi * ( - 2.4774111897080783e-01
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+ cosphi * ( + 8.5438256055858031e-02
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+ cosphi * ( - 1.2320203369293225e-02
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+ cosphi * ( + 4.3778825791773474e-04 ))))));
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break;
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}
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coef = scale * sinc * window;
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switch (rtype)
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{
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case 0:
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c_impulse[i] = + coef * cos (posi * w_osc);
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c_impulse[j] = + coef * cos (posj * w_osc);
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break;
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case 1:
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c_impulse[2 * i + 0] = + coef * cos (posi * w_osc);
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c_impulse[2 * i + 1] = - coef * sin (posi * w_osc);
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c_impulse[2 * j + 0] = + coef * cos (posj * w_osc);
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c_impulse[2 * j + 1] = - coef * sin (posj * w_osc);
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break;
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}
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}
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return c_impulse;
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}
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2024-06-25 01:50:48 +00:00
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float *FIR::fir_read (int N, const char *filename, int rtype, float scale)
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2024-06-16 09:31:13 +00:00
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// N = number of real or complex coefficients (see rtype)
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// *filename = filename
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// rtype = 0: real coefficients
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// rtype = 1: complex coefficients
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// scale = a scale factor that will be applied to the returned coefficients;
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// if this is not needed, set it to 1.0
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// NOTE: The number of values in the file must NOT exceed those implied by N and rtype
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{
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FILE *file;
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int i;
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2024-06-25 01:50:48 +00:00
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float I, Q;
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float *c_impulse = new float[N * 2]; // (float *) malloc0 (N * sizeof (complex));
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2024-06-16 09:31:13 +00:00
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file = fopen (filename, "r");
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for (i = 0; i < N; i++)
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{
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// read in the complex impulse response
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// NOTE: IF the freq response is symmetrical about 0, the imag coeffs will all be zero.
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switch (rtype)
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{
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case 0:
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{
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2024-06-25 01:50:48 +00:00
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int r = fscanf (file, "%e", &I);
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2024-06-16 09:31:13 +00:00
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fprintf(stderr, "^%d parameters read\n", r);
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c_impulse[i] = + scale * I;
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break;
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}
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case 1:
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{
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2024-06-25 01:50:48 +00:00
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int r = fscanf (file, "%e", &I);
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2024-06-16 09:31:13 +00:00
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fprintf(stderr, "%d parameters read\n", r);
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2024-06-25 01:50:48 +00:00
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r = fscanf (file, "%e", &Q);
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2024-06-16 09:31:13 +00:00
|
|
|
fprintf(stderr, "%d parameters read\n", r);
|
|
|
|
c_impulse[2 * i + 0] = + scale * I;
|
|
|
|
c_impulse[2 * i + 1] = - scale * Q;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
fclose (file);
|
|
|
|
return c_impulse;
|
|
|
|
}
|
|
|
|
|
2024-06-25 01:50:48 +00:00
|
|
|
void FIR::analytic (int N, float* in, float* out)
|
2024-06-16 09:31:13 +00:00
|
|
|
{
|
|
|
|
int i;
|
2024-07-16 23:58:47 +00:00
|
|
|
float inv_N = 1.0 / (float) N;
|
2024-06-25 01:50:48 +00:00
|
|
|
float two_inv_N = 2.0 * inv_N;
|
|
|
|
float* x = new float[N * 2]; // (float *) malloc0 (N * sizeof (complex));
|
2024-07-16 23:58:47 +00:00
|
|
|
fftwf_plan pfor = fftwf_plan_dft_1d (
|
|
|
|
N,
|
|
|
|
(fftwf_complex *) in,
|
|
|
|
(fftwf_complex *) x,
|
|
|
|
FFTW_FORWARD,
|
|
|
|
FFTW_PATIENT
|
|
|
|
);
|
|
|
|
fftwf_plan prev = fftwf_plan_dft_1d (
|
|
|
|
N,
|
|
|
|
(fftwf_complex *) x,
|
|
|
|
(fftwf_complex *) out,
|
|
|
|
FFTW_BACKWARD,
|
|
|
|
FFTW_PATIENT
|
|
|
|
);
|
2024-06-25 01:50:48 +00:00
|
|
|
fftwf_execute (pfor);
|
2024-06-16 09:31:13 +00:00
|
|
|
x[0] *= inv_N;
|
|
|
|
x[1] *= inv_N;
|
|
|
|
for (i = 1; i < N / 2; i++)
|
|
|
|
{
|
|
|
|
x[2 * i + 0] *= two_inv_N;
|
|
|
|
x[2 * i + 1] *= two_inv_N;
|
|
|
|
}
|
|
|
|
x[N + 0] *= inv_N;
|
|
|
|
x[N + 1] *= inv_N;
|
2024-06-25 01:50:48 +00:00
|
|
|
memset (&x[N + 2], 0, (N - 2) * sizeof (float));
|
|
|
|
fftwf_execute (prev);
|
|
|
|
fftwf_destroy_plan (prev);
|
|
|
|
fftwf_destroy_plan (pfor);
|
2024-06-16 09:31:13 +00:00
|
|
|
delete[] x;
|
|
|
|
}
|
|
|
|
|
2024-06-25 01:50:48 +00:00
|
|
|
void FIR::mp_imp (int N, float* fir, float* mpfir, int pfactor, int polarity)
|
2024-06-16 09:31:13 +00:00
|
|
|
{
|
|
|
|
int i;
|
|
|
|
int size = N * pfactor;
|
2024-07-16 23:58:47 +00:00
|
|
|
double inv_PN = 1.0 / (float)size;
|
|
|
|
float* firpad = new float[size * 2]; // (float *) malloc0 (size * sizeof (complex));
|
|
|
|
float* firfreq = new float[size * 2]; // (float *) malloc0 (size * sizeof (complex));
|
|
|
|
double* mag = new double[size]; // (float *) malloc0 (size * sizeof (float));
|
|
|
|
float* ana = new float[size * 2]; // (float *) malloc0 (size * sizeof (complex));
|
|
|
|
float* impulse = new float[size * 2]; // (float *) malloc0 (size * sizeof (complex));
|
|
|
|
float* newfreq = new float[size * 2]; // (float *) malloc0 (size * sizeof (complex));
|
2024-07-16 21:15:13 +00:00
|
|
|
std::copy(fir, fir + N * 2, firpad);
|
2024-07-16 23:58:47 +00:00
|
|
|
fftwf_plan pfor = fftwf_plan_dft_1d (
|
|
|
|
size,
|
|
|
|
(fftwf_complex *) firpad,
|
|
|
|
(fftwf_complex *) firfreq,
|
|
|
|
FFTW_FORWARD,
|
|
|
|
FFTW_PATIENT);
|
|
|
|
fftwf_plan prev = fftwf_plan_dft_1d (
|
|
|
|
size,
|
|
|
|
(fftwf_complex *) newfreq,
|
|
|
|
(fftwf_complex *) impulse,
|
|
|
|
FFTW_BACKWARD,
|
|
|
|
FFTW_PATIENT
|
|
|
|
);
|
2024-06-16 09:31:13 +00:00
|
|
|
// print_impulse("orig_imp.txt", N, fir, 1, 0);
|
2024-06-25 01:50:48 +00:00
|
|
|
fftwf_execute (pfor);
|
2024-06-16 09:31:13 +00:00
|
|
|
for (i = 0; i < size; i++)
|
|
|
|
{
|
2024-07-16 23:58:47 +00:00
|
|
|
double xr = firfreq[2 * i + 0];
|
|
|
|
double xi = firfreq[2 * i + 1];
|
|
|
|
mag[i] = sqrt (xr*xr + xi*xi) * inv_PN;
|
2024-06-16 09:31:13 +00:00
|
|
|
if (mag[i] > 0.0)
|
|
|
|
ana[2 * i + 0] = log (mag[i]);
|
|
|
|
else
|
2024-07-17 01:04:47 +00:00
|
|
|
ana[2 * i + 0] = log (std::numeric_limits<float>::min());
|
2024-06-16 09:31:13 +00:00
|
|
|
}
|
|
|
|
analytic (size, ana, ana);
|
|
|
|
for (i = 0; i < size; i++)
|
|
|
|
{
|
|
|
|
newfreq[2 * i + 0] = + mag[i] * cos (ana[2 * i + 1]);
|
|
|
|
if (polarity)
|
|
|
|
newfreq[2 * i + 1] = + mag[i] * sin (ana[2 * i + 1]);
|
|
|
|
else
|
|
|
|
newfreq[2 * i + 1] = - mag[i] * sin (ana[2 * i + 1]);
|
|
|
|
}
|
2024-06-25 01:50:48 +00:00
|
|
|
fftwf_execute (prev);
|
2024-06-16 09:31:13 +00:00
|
|
|
if (polarity)
|
2024-07-16 21:15:13 +00:00
|
|
|
std::copy(&impulse[2 * (pfactor - 1) * N], &impulse[2 * (pfactor - 1) * N] + N * 2, mpfir);
|
2024-06-16 09:31:13 +00:00
|
|
|
else
|
2024-07-16 21:15:13 +00:00
|
|
|
std::copy(impulse, impulse + N * 2, mpfir);
|
2024-06-16 09:31:13 +00:00
|
|
|
// print_impulse("min_imp.txt", N, mpfir, 1, 0);
|
2024-06-25 01:50:48 +00:00
|
|
|
fftwf_destroy_plan (prev);
|
|
|
|
fftwf_destroy_plan (pfor);
|
2024-06-16 09:31:13 +00:00
|
|
|
delete[] (newfreq);
|
|
|
|
delete[] (impulse);
|
|
|
|
delete[] (ana);
|
|
|
|
delete[] (mag);
|
|
|
|
delete[] (firfreq);
|
|
|
|
delete[] (firpad);
|
|
|
|
}
|
|
|
|
|
|
|
|
// impulse response of a zero frequency filter comprising a cascade of two resonators,
|
|
|
|
// each followed by a detrending filter
|
2024-06-25 01:50:48 +00:00
|
|
|
float* FIR::zff_impulse(int nc, float scale)
|
2024-06-16 09:31:13 +00:00
|
|
|
{
|
|
|
|
// nc = number of coefficients (power of two)
|
|
|
|
int n_resdet = nc / 2 - 1; // size of single zero-frequency resonator with detrender
|
|
|
|
int n_dresdet = 2 * n_resdet - 1; // size of two cascaded units; when we convolve these we get 2 * n - 1 length
|
|
|
|
// allocate the single and make the values
|
2024-06-25 01:50:48 +00:00
|
|
|
float* resdet = new float[n_resdet]; // (float*)malloc0 (n_resdet * sizeof(float));
|
2024-06-16 09:31:13 +00:00
|
|
|
for (int i = 1, j = 0, k = n_resdet - 1; i < nc / 4; i++, j++, k--)
|
2024-06-25 01:50:48 +00:00
|
|
|
resdet[j] = resdet[k] = (float)(i * (i + 1) / 2);
|
|
|
|
resdet[nc / 4 - 1] = (float)(nc / 4 * (nc / 4 + 1) / 2);
|
2024-06-16 09:31:13 +00:00
|
|
|
// print_impulse ("resdet", n_resdet, resdet, 0, 0);
|
2024-06-25 01:50:48 +00:00
|
|
|
// allocate the float and complex versions and make the values
|
|
|
|
float* dresdet = new float[n_dresdet]; // (float*)malloc0 (n_dresdet * sizeof(float));
|
|
|
|
float div = (float)((nc / 2 + 1) * (nc / 2 + 1)); // calculate divisor
|
|
|
|
float* c_dresdet = new float[nc * 2]; // (float*)malloc0 (nc * sizeof(complex));
|
2024-06-16 09:31:13 +00:00
|
|
|
for (int n = 0; n < n_dresdet; n++) // convolve to make the cascade
|
|
|
|
{
|
|
|
|
for (int k = 0; k < n_resdet; k++)
|
|
|
|
if ((n - k) >= 0 && (n - k) < n_resdet)
|
|
|
|
dresdet[n] += resdet[k] * resdet[n - k];
|
|
|
|
dresdet[n] /= div;
|
|
|
|
c_dresdet[2 * n + 0] = dresdet[n] * scale;
|
|
|
|
c_dresdet[2 * n + 1] = 0.0;
|
|
|
|
}
|
|
|
|
// print_impulse("dresdet", n_dresdet, dresdet, 0, 0);
|
|
|
|
// print_impulse("c_dresdet", nc, c_dresdet, 1, 0);
|
|
|
|
delete[] (dresdet);
|
|
|
|
delete[] (resdet);
|
|
|
|
return c_dresdet;
|
|
|
|
}
|
|
|
|
|
|
|
|
} // namespace WDSP
|