mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-30 03:38:55 -05:00
402 lines
10 KiB
C++
402 lines
10 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2023 Edouard Griffiths, F4EXB. //
|
|
// //
|
|
// This is the code from ft8mon: https://github.com/rtmrtmrtmrtm/ft8mon //
|
|
// written by Robert Morris, AB1HL //
|
|
// reformatted and adapted to Qt and SDRangel context //
|
|
// //
|
|
// 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 <assert.h>
|
|
#include <fftw3.h>
|
|
#include <QDebug>
|
|
#include "fft.h"
|
|
#include "util.h"
|
|
#include "ft8plan.h"
|
|
#include "ft8plans.h"
|
|
#include "fftbuffers.h"
|
|
|
|
namespace FT8 {
|
|
|
|
FFTEngine::FFTEngine()
|
|
{
|
|
m_fftBuffers = new FFTBuffers();
|
|
}
|
|
|
|
FFTEngine::~FFTEngine()
|
|
{
|
|
delete m_fftBuffers;
|
|
}
|
|
|
|
//
|
|
// do just one FFT on samples[i0..i0+block]
|
|
// real inputs, complex outputs.
|
|
// output has (block / 2) + 1 points.
|
|
//
|
|
std::vector<std::complex<float>> FFTEngine::one_fft(
|
|
const std::vector<float> &samples,
|
|
int i0,
|
|
int block
|
|
)
|
|
{
|
|
// assert(i0 >= 0);
|
|
// assert(block > 1);
|
|
|
|
int nsamples = samples.size();
|
|
int nbins = (block / 2) + 1;
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
|
|
fftwf_plan plan = p->fwd_;
|
|
|
|
// assert((int)samples.size() - i0 >= block);
|
|
|
|
float *m_in = (float *)samples.data() + i0;
|
|
|
|
if ((((unsigned long long)m_in) % 16) != 0)
|
|
{
|
|
// m_in must be on a 16-byte boundary for FFTW.
|
|
m_in = m_fftBuffers->getR(p->n_);
|
|
// assert(m_in);
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
if (i0 + i < nsamples)
|
|
{
|
|
m_in[i] = samples[i0 + i];
|
|
}
|
|
else
|
|
{
|
|
m_in[i] = 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
fftwf_complex *m_out = m_fftBuffers->getC(p->n_);
|
|
// assert(m_out);
|
|
|
|
fftwf_execute_dft_r2c(plan, m_in, m_out);
|
|
|
|
std::vector<std::complex<float>> out(nbins);
|
|
|
|
for (int bi = 0; bi < nbins; bi++)
|
|
{
|
|
float re = m_out[bi][0];
|
|
float im = m_out[bi][1];
|
|
out[bi] = std::complex<float>(re, im);
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
//
|
|
// do a full set of FFTs, one per symbol-time.
|
|
// bins[time][frequency]
|
|
//
|
|
FFTEngine::ffts_t FFTEngine::ffts(const std::vector<float> &samples, int i0, int block)
|
|
{
|
|
// assert(i0 >= 0);
|
|
// assert(block > 1 && (block % 2) == 0);
|
|
|
|
int nsamples = samples.size();
|
|
int nbins = (block / 2) + 1;
|
|
int nblocks = (nsamples - i0) / block;
|
|
ffts_t bins(nblocks);
|
|
|
|
for (int si = 0; si < nblocks; si++) {
|
|
bins[si].resize(nbins);
|
|
}
|
|
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
fftwf_plan plan = p->fwd_;
|
|
|
|
// allocate our own b/c using p->m_in and p->m_out isn't thread-safe.
|
|
float *m_in = m_fftBuffers->getR(p->n_);
|
|
fftwf_complex *m_out = m_fftBuffers->getC(p->n_);
|
|
// assert(m_in && m_out);
|
|
|
|
// float *m_in = p->r_;
|
|
// fftw_complex *m_out = p->c_;
|
|
|
|
for (int si = 0; si < nblocks; si++)
|
|
{
|
|
int off = i0 + si * block;
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
if (off + i < nsamples)
|
|
{
|
|
float x = samples[off + i];
|
|
m_in[i] = x;
|
|
}
|
|
else
|
|
{
|
|
m_in[i] = 0;
|
|
}
|
|
}
|
|
|
|
fftwf_execute_dft_r2c(plan, m_in, m_out);
|
|
|
|
for (int bi = 0; bi < nbins; bi++)
|
|
{
|
|
float re = m_out[bi][0];
|
|
float im = m_out[bi][1];
|
|
std::complex<float> c(re, im);
|
|
bins[si][bi] = c;
|
|
}
|
|
}
|
|
|
|
return bins;
|
|
}
|
|
|
|
//
|
|
// do just one FFT on samples[i0..i0+block]
|
|
// real inputs, complex outputs.
|
|
// output has block points.
|
|
//
|
|
std::vector<std::complex<float>> FFTEngine::one_fft_c(
|
|
const std::vector<float> &samples,
|
|
int i0,
|
|
int block
|
|
)
|
|
{
|
|
// assert(i0 >= 0);
|
|
// assert(block > 1);
|
|
|
|
int nsamples = samples.size();
|
|
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
fftwf_plan plan = p->cfwd_;
|
|
|
|
fftwf_complex *m_in = m_fftBuffers->getCCI(block);
|
|
fftwf_complex *m_out = m_fftBuffers->getCCO(block);
|
|
// assert(m_in && m_out);
|
|
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
if (i0 + i < nsamples)
|
|
{
|
|
m_in[i][0] = samples[i0 + i]; // real
|
|
}
|
|
else
|
|
{
|
|
m_in[i][0] = 0;
|
|
}
|
|
m_in[i][1] = 0; // imaginary
|
|
}
|
|
|
|
fftwf_execute_dft(plan, m_in, m_out);
|
|
|
|
std::vector<std::complex<float>> out(block);
|
|
float norm = 1.0 / sqrt(block);
|
|
|
|
for (int bi = 0; bi < block; bi++)
|
|
{
|
|
float re = m_out[bi][0];
|
|
float im = m_out[bi][1];
|
|
std::complex<float> c(re, im);
|
|
c *= norm;
|
|
out[bi] = c;
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
std::vector<std::complex<float>> FFTEngine::one_fft_cc(
|
|
const std::vector<std::complex<float>> &samples,
|
|
int i0,
|
|
int block
|
|
)
|
|
{
|
|
// assert(i0 >= 0);
|
|
// assert(block > 1);
|
|
|
|
int nsamples = samples.size();
|
|
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
fftwf_plan plan = p->cfwd_;
|
|
|
|
fftwf_complex *m_in = m_fftBuffers->getCCI(block);
|
|
fftwf_complex *m_out = m_fftBuffers->getCCO(block);
|
|
// assert(m_in && m_out);
|
|
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
if (i0 + i < nsamples)
|
|
{
|
|
m_in[i][0] = samples[i0 + i].real();
|
|
m_in[i][1] = samples[i0 + i].imag();
|
|
}
|
|
else
|
|
{
|
|
m_in[i][0] = 0;
|
|
m_in[i][1] = 0;
|
|
}
|
|
}
|
|
|
|
fftwf_execute_dft(plan, m_in, m_out);
|
|
|
|
std::vector<std::complex<float>> out(block);
|
|
|
|
// float norm = 1.0 / sqrt(block);
|
|
for (int bi = 0; bi < block; bi++)
|
|
{
|
|
float re = m_out[bi][0];
|
|
float im = m_out[bi][1];
|
|
std::complex<float> c(re, im);
|
|
// c *= norm;
|
|
out[bi] = c;
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
std::vector<std::complex<float>> FFTEngine::one_ifft_cc(
|
|
const std::vector<std::complex<float>> &bins
|
|
)
|
|
{
|
|
int block = bins.size();
|
|
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
fftwf_plan plan = p->crev_;
|
|
|
|
fftwf_complex *m_in = m_fftBuffers->getCCI(block);
|
|
fftwf_complex *m_out = m_fftBuffers->getCCO(block);
|
|
// assert(m_in && m_out);
|
|
|
|
for (int bi = 0; bi < block; bi++)
|
|
{
|
|
float re = bins[bi].real();
|
|
float im = bins[bi].imag();
|
|
m_in[bi][0] = re;
|
|
m_in[bi][1] = im;
|
|
}
|
|
|
|
fftwf_execute_dft(plan, m_in, m_out);
|
|
|
|
std::vector<std::complex<float>> out(block);
|
|
float norm = 1.0 / sqrt(block);
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
float re = m_out[i][0];
|
|
float im = m_out[i][1];
|
|
std::complex<float> c(re, im);
|
|
c *= norm;
|
|
out[i] = c;
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
std::vector<float> FFTEngine::one_ifft(const std::vector<std::complex<float>> &bins)
|
|
{
|
|
int nbins = bins.size();
|
|
int block = (nbins - 1) * 2;
|
|
|
|
Plan *p = FT8Plans::GetInstance()->getPlan(block);
|
|
fftwf_plan plan = p->rev_;
|
|
|
|
fftwf_complex *m_in = m_fftBuffers->getC(p->n_);
|
|
float *m_out = m_fftBuffers->getR(p->n_);
|
|
|
|
for (int bi = 0; bi < nbins; bi++)
|
|
{
|
|
float re = bins[bi].real();
|
|
float im = bins[bi].imag();
|
|
m_in[bi][0] = re;
|
|
m_in[bi][1] = im;
|
|
}
|
|
|
|
fftwf_execute_dft_c2r(plan, m_in, m_out);
|
|
|
|
std::vector<float> out(block);
|
|
for (int i = 0; i < block; i++)
|
|
{
|
|
out[i] = m_out[i];
|
|
}
|
|
|
|
return out;
|
|
}
|
|
|
|
//
|
|
// return the analytic signal for signal x,
|
|
// just like scipy.signal.hilbert(), from which
|
|
// this code is copied.
|
|
//
|
|
// the return value is x + iy, where y is the hilbert transform of x.
|
|
//
|
|
std::vector<std::complex<float>> FFTEngine::analytic(const std::vector<float> &x)
|
|
{
|
|
ulong n = x.size();
|
|
|
|
std::vector<std::complex<float>> y = one_fft_c(x, 0, n);
|
|
// assert(y.size() == n);
|
|
|
|
// leave y[0] alone.
|
|
// float the first (positive) half of the spectrum.
|
|
// zero out the second (negative) half of the spectrum.
|
|
// y[n/2] is the nyquist bucket if n is even; leave it alone.
|
|
if ((n % 2) == 0)
|
|
{
|
|
for (ulong i = 1; i < n / 2; i++)
|
|
y[i] *= 2;
|
|
for (ulong i = n / 2 + 1; i < n; i++)
|
|
y[i] = 0;
|
|
}
|
|
else
|
|
{
|
|
for (ulong i = 1; i < (n + 1) / 2; i++)
|
|
y[i] *= 2;
|
|
for (ulong i = (n + 1) / 2; i < n; i++)
|
|
y[i] = 0;
|
|
}
|
|
|
|
std::vector<std::complex<float>> z = one_ifft_cc(y);
|
|
|
|
return z;
|
|
}
|
|
|
|
//
|
|
// general-purpose shift x in frequency by hz.
|
|
// uses hilbert transform to avoid sidebands.
|
|
// but it does wrap around at 0 hz and the nyquist frequency.
|
|
//
|
|
// note analytic() does an FFT over the whole signal, which
|
|
// is expensive, and often re-used, but it turns out it
|
|
// isn't a big factor in overall run-time.
|
|
//
|
|
// like weakutil.py's freq_shift().
|
|
//
|
|
std::vector<float> FFTEngine::hilbert_shift(const std::vector<float> &x, float hz0, float hz1, int rate)
|
|
{
|
|
// y = scipy.signal.hilbert(x)
|
|
std::vector<std::complex<float>> y = analytic(x);
|
|
// assert(y.size() == x.size());
|
|
|
|
float dt = 1.0 / rate;
|
|
int n = x.size();
|
|
|
|
std::vector<float> ret(n);
|
|
|
|
for (int i = 0; i < n; i++)
|
|
{
|
|
// complex "local oscillator" at hz.
|
|
float hz = hz0 + (i / (float)n) * (hz1 - hz0);
|
|
std::complex<float> lo = std::exp(std::complex<float>(0.0, 2 * M_PI * hz * dt * i));
|
|
ret[i] = (lo * y[i]).real();
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
} // namespace FT8
|