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sdrangel/sdrbench/test_fftrrc.cpp
2026-02-12 23:23:27 +01:00

78 lines
3.2 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2026 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
// //
// 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 as 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 V3 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/>. //
///////////////////////////////////////////////////////////////////////////////////
#include "mainbench.h"
#include "dsp/fftfilterrrc.h"
#include <QDebug>
void MainBench::testFFTRRCFilter()
{
qDebug() << "MainBench::testFFTRRCFilter";
const int RRC_FFT_SIZE = 512;
std::complex<float>* rrcFilterOut = nullptr;
FFTFilterRRC filter(RRC_FFT_SIZE);
filter.create(0.05f, 0.35f); // 2400 baud, 0.35 rolloff
qDebug() << "MainBench::testFFTRRCFilter: filter created";
FILE *fd_filter = fopen("test_rrc_filter.txt", "w");
for (int i = 0; i < RRC_FFT_SIZE; i++) {
fprintf(fd_filter, "%f\n", std::abs(filter.getFilter()[i]));
}
qDebug() << "MainBench::testFFTRRCFilter: filter coefficients written to test_rrc_filter.txt";
fclose(fd_filter);
qDebug() << "MainBench::testFFTRRCFilter: running filter";
FILE *fd = fopen("test_rrc.txt", "w");
int outLen = 0;
for (int i = 0; i < 5000; i++)
{
int ss = 48000 / 2400; // Samples per symbol at 2400 baud
int d = i / ss; // Symbol index at 2400 baud
Real s = (d % 2 == 0) ? 1.0f : -1.0f; // BPSK symbol sequence
Real x = (i % ss == 0 ? s : 0.0f); // Pulsed signal at 2400 Hz
// Real phi = i * (1200.0 / 48000.0) * (2*3.141);
// Real x = sin(phi) > 0.0 ? 1.0f : -1.0f; // Simulate a BPSK signal at 1200 baud
filter.process(Complex(x, 0.0f), &rrcFilterOut);
outLen++;
if (outLen % (RRC_FFT_SIZE / 2) == 0)
{
// printf("\ni=%d n_out: %d\n", i, n_out);
for (int j = 0; j < outLen; j++)
{
Complex rrc = rrcFilterOut[j];
fprintf(fd, "%f\n", rrc.real());
}
outLen = 0;
}
}
// output any remaining samples
for (int j = 0; j < outLen; j++)
{
Complex rrc = rrcFilterOut[j];
fprintf(fd, "%f\n", rrc.real());
}
qDebug() << "MainBench::testFFTRRCFilter: output samples written to test_fftrrc.txt";
fclose(fd);
}