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fftscope.cpp
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fftscope.cpp
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#include "fftscope.h"
#include <qtimer.h>
#include <qpainter.h>
#include <qapplication.h>
#include <qtimer.h>
#include<sys/ioctl.h>
#include<stdio.h>
#include<fcntl.h>
#include<unistd.h>
#include<stdlib.h>
#include<math.h>
#include <comedilib.h>
#include <fcntl.h>
#include <fftw3.h>
#include <qwt/qwt_plot.h>
#include <qwt/qwt_plot_curve.h>
#include "comedirecord.h"
FFTScope::FFTScope( ComediRecord *parent, int fft_buffer_size)
: QMainWindow( parent, 0 )
{
comedirecord=parent;
setAttribute(Qt::WA_DeleteOnClose);
setWindowFlags(Qt::Window);
counter = new QTimer( this );
connect( counter,
SIGNAL(timeout()),
this,
SLOT(updateFFT()) );
counter->start( FFT_UPDATE_DELAY );
buffer_size = fft_buffer_size;
// fft init
// real numbers in
in = (double*)fftw_malloc(sizeof(double) * buffer_size);
int n_out = ((buffer_size/2)+1);
// complex numbers out
out = (fftw_complex*)fftw_malloc(sizeof(fftw_complex) * n_out);
current_entry = 0;
filled = 0;
nFreqSamples = round(((double)(comedirecord->comediScope->fftmaxfrequency))/
(comedirecord->comediScope->sampling_rate/((double)buffer_size)))/2;
nFreqSamples++;
if (nFreqSamples > (buffer_size/2)) {
nFreqSamples = (buffer_size/2);
}
// plotting
fftPlot = new QwtPlot(this);
fftPlot->setAxisAutoScale(QwtPlot::yLeft,true);
fftPlot->setAxisAutoScale(QwtPlot::xBottom,true);
QwtPlotCurve *fftCurve = new QwtPlotCurve("FFT");
x = new double[nFreqSamples];
y = new double[nFreqSamples];
for(int i=0;i<nFreqSamples;i++) {
x[i]=0.0;
y[i]=0.0;
}
fftCurve->setRawSamples(x,y,nFreqSamples);
fftCurve->attach(fftPlot);
setCentralWidget(fftPlot);
}
FFTScope::~FFTScope()
{
comedirecord->comediScope->fftch = -1;
comedirecord->comediScope->fftdevno = -1;
counter->stop();
delete counter;
fftw_free ( in );
fftw_free ( out );
delete []x;
delete []y;
}
void FFTScope::updateFFT()
{
if (filled)
{
int i;
fftw_plan plan_forward;
// real in and complex out
plan_forward = fftw_plan_dft_r2c_1d ( buffer_size, in, out, FFTW_ESTIMATE );
// do it
fftw_execute ( plan_forward );
// plot the spectrum
float yMax = 1E-10;
double f = 1;
for (i = 0; i < nFreqSamples; i++)
{
f = ((double)i)*comedirecord->comediScope->sampling_rate/((double)buffer_size);
x[i] = f;
double a = out[i][0];
double b = out[i][1];
y[i] = sqrt(a*a+b*b) / nFreqSamples;
if ((y[i]>yMax)&&(i>0)) yMax = y[i];
}
y[0]=0.0;
fftPlot->setAxisScale(QwtPlot::yLeft,0,yMax);
fftPlot->setAxisScale(QwtPlot::xBottom,0,f);
fftw_destroy_plan ( plan_forward );
fftPlot->replot();
filled = 0;
current_entry = 0;
}
}
int FFTScope::append(double val)
{
in[current_entry] = val ;
current_entry++ ;
if (current_entry == buffer_size)
{
current_entry = 0;
filled = 1;
}
return filled;
}