/****************************************************************************
* GetfittingMetrics
* calculate the fitting parameters that the user is interested in
****************************************************************************/
public FittingMetrics GetFittingMetrics(LorentzParams lp, FFTSettings fftSettings)
{
FittingMetrics fm = new FittingMetrics
{
amplitude = lp.A / lp.gamma / lp.gamma + lp.up,
f0 = lp.f0
};
double ampPrime = 0;
switch (fftSettings.Fftstyle)
{
case 0: //Log (dB)
ampPrime = fm.amplitude - 3;
break;
case 1: // Log - Complex Conjugate (dB)
ampPrime = fm.amplitude - 3;
break;
case 2: // Magnitude (V)
ampPrime = fm.amplitude * 0.5;
break;
case 3: // Magnitude - Complex Conjugate (V)
ampPrime = fm.amplitude * 0.5;
break;
}
try
{
fm.f1 = fm.f0 + Math.Sqrt((lp.A + lp.gamma * lp.gamma * (lp.up - ampPrime)) / (ampPrime - lp.up));
fm.f2 = fm.f0 - Math.Sqrt((lp.A + lp.gamma * lp.gamma * (lp.up - ampPrime)) / (ampPrime - lp.up));
}
catch (Exception)
{
fm.f1 = 0;
fm.f2 = 0;
}
if (fm.f1 - fm.f2 > 0)
{
fm.Q = fm.f0 / (fm.f1 - fm.f2);
}
else
{
fm.Q = 0;
}
return(fm);
}
// FFT CALCULATIONS //
/****************************************************************************
* GetFFT
* Get the raw FFT of an array
****************************************************************************/
private FFTData GetFFT(int[] amp, int[] time, FFTSettings fftSettings, double[] lastfft, int SampleCount)
{
FFTData fftData = new FFTData();
double[] fft = new double[amp.Length];
double[] freq = new double[amp.Length / 2];
//AForge.Math.Complex[] fftComplex = new AForge.Math.Complex[amp.Length];
Complex[] fftComplex = new Complex[amp.Length];
// if FFT style has changed, reset the averaging by making last FFT null.
if (fftSettings.isFftStyleChange)
{
lastfft = null;
}
//calculate fft
for (int i = 0; i < amp.Length; i++)
{
//fftComplex[i] = new AForge.Math.Complex();
fftComplex[i] = new Complex(amp[i], 0);
}
//AForge.Math.FourierTransform.FFT(fftComplex, AForge.Math.FourierTransform.Direction.Forward);
Accord.Math.Transforms.FourierTransform2.FFT(fftComplex, Accord.Math.FourierTransform.Direction.Forward);
// transform fft based on user selected style
for (int i = 0; i < amp.Length; i++)
{
time[i] = time[i] - time.Min();
switch (fftSettings.Fftstyle)
{
case 0: //Log
fft[i] = 20 * Math.Log10(fftComplex[i].Magnitude); // decibels=20Log, http://www.arrl.org/files/file/Instructor%20resources/A%20Tutorial%20on%20the%20Dec-N0AX.pdf
if (fft[i] == Double.NegativeInfinity || fft[i] == Double.NaN)
{
fft[i] = 0;
}
break;
case 1: // Log - Complex Conjugate
fft[i] = 20 * Math.Log10(Complex.Conjugate(fftComplex[i]).Magnitude *fftComplex[i].Magnitude);
if (fft[i] == Double.NegativeInfinity || fft[i] == Double.NaN)
{
fft[i] = 0;
}
break;
case 2: // Magnitude
fft[i] = fftComplex[i].Magnitude;
break;
case 3: // Magnitude - Complex Conjugate
fft[i] = Complex.Conjugate(fftComplex[i]).Magnitude *fftComplex[i].Magnitude;
break;
default:
break;
}
if (i % 2 == 0)
{
freq[i / 2] = /*Math.Pow(2,1024/SampleCount-1) */ (1024 / SampleCount) * Convert.ToDouble(i / 2) * 1e3 / (time[9] - time[8]);
}
}
fft = fft.Take(fft.Length / 2).ToArray();
// transform FFT based on user selected averaging technique- New Average = (New Spectrum • 1/N) + (Old Average) • (N−1)/N
if (lastfft == null)
{
fftSettings.isFftMovAvg = false;
fftSettings.isFftContAvg = false;
}
if (fftSettings.isFftMovAvg)
{
for (int i = 0; i < fft.Length; i++)
{
fft[i] = fft[i] * 1 / fftSettings.nFftMovAvg + lastfft[i] * (fftSettings.nFftMovAvg - 1) / fftSettings.nFftMovAvg;
}
}
if (fftSettings.isFftContAvg)
{
for (int i = 0; i < fft.Length; i++)
{
try
{
fft[i] = fft[i] * 1 / fftSettings.nFftContAvg + lastfft[i] * (fftSettings.nFftContAvg - 1) / fftSettings.nFftContAvg;
}
catch (Exception)
{
}
}
fftSettings.nFftContAvg++;
}
fftData.fft = fft;
fftData.freq = freq;
return(fftData);
}
/****************************************************************************
* GetPlottableData
* this function demonstrates how to collect a single block of data
* from the unit (start collecting immediately)
****************************************************************************/
public PlottableData GetPlottableData(short handle, Pico.ChannelSettings[] channelSettings, FFTSettings fftSettings, double[] lastfft, ref ProcessTimes processTimes, ref System.Windows.Forms.Timer WaveFormTimer, int SampleCount, bool isChanelB)
{
Stopwatch sw = new Stopwatch();
//sw.Start();
WaveFormData waveFormData = new WaveFormData();
// Method that communicates with Pico to get blocked data
HandlePicoBlockData(0, channelSettings, handle, ref waveFormData, ref processTimes, ref WaveFormTimer, SampleCount, isChanelB);
//sw.Stop();
//return if it's chanel B
if (isChanelB)
{
return new PlottableData {
fftData = new FFTData(), WaveFormData = waveFormData
}
}
;
// calculate fft data if is not chanel B
sw.Restart();
PlottableData plottableData = new PlottableData {
fftData = GetFFT(waveFormData.amp, waveFormData.time, fftSettings, lastfft, SampleCount), WaveFormData = waveFormData
};
sw.Stop();
processTimes.fftTime = sw.Elapsed;
return(plottableData);
}
