public void Process(Complex *buffer, int length)
{
if (_workingBuffer == null || _workingBuffer.Length < length)
{
_workingBuffer = new Complex[length];
}
for (var n = 0; n < length; n++)
{
_workingBuffer[n] = buffer[n];
}
if (_window == null || _window.Length < length)
_window = FilterBuilder.MakeWindow(WindowType.Hamming, length);
fixed(Complex *workingPtr = &_workingBuffer[0])
{
fixed(float *winPtr = &_window[0])
Fourier.ApplyFFTWindow(workingPtr, winPtr, length);
Fourier.ForwardTransform(workingPtr, length);
_drawing.AddDataLine(workingPtr, length);
}
//_drawing.AddDataLine(buffer, length);
}
private void ProcessFFT(object parameter)
{
while (_control.IsPlaying && _fftThreadRunning)
{
#region Configure
if (_sampleRate == 0.0)
{
// WTF???
Thread.Sleep(1);
continue;
}
var fftRate = _fftBins / (_fftTimer.Interval * 0.001);
_fftOverlapRatio = _sampleRate / fftRate;
var samplesToConsume = (int)(_fftBins * _fftOverlapRatio);
_fftSamplesPerFrame = Math.Min(samplesToConsume, _fftBins);
var excessSamples = samplesToConsume - _fftSamplesPerFrame;
_maxIQSamples = (int)(samplesToConsume / (double)_fftTimer.Interval * 100 * /*_streamControl.BufferSizeInMs **/ 1.5);
#endregion
#region Shift data for overlapped mode)
if (_fftSamplesPerFrame < _fftBins)
{
Utils.Memcpy(_iqPtr, _iqPtr + _fftSamplesPerFrame, (_fftBins - _fftSamplesPerFrame) * sizeof(Complex));
}
#endregion
#region Read IQ data
var targetLength = _fftSamplesPerFrame;
var total = 0;
while (_control.IsPlaying && total < targetLength && _fftThreadRunning)
{
var len = targetLength - total;
total += _iqStream.Read(_iqPtr, _fftBins - targetLength + total, len);
}
_iqStream.Advance(excessSamples);
#endregion
if (!_fftSpectrumAvailable)
{
#region Process FFT gain
// http://www.designnews.com/author.asp?section_id=1419&doc_id=236273&piddl_msgid=522392
var fftGain = (float)(10.0 * Math.Log10((double)_fftBins / 2));
var compensation = 24.0f - fftGain + _fftOffset;
#endregion
#region Calculate FFT
Utils.Memcpy(_fftPtr, _iqPtr, _fftBins * sizeof(Complex));
Fourier.ApplyFFTWindow(_fftPtr, _fftWindowPtr, _fftBins);
Fourier.ForwardTransform(_fftPtr, _fftBins);
Fourier.SpectrumPower((Complex *)_fftPtr, (float *)_fftSpectrumPtr, (int)_fftBins, (float)compensation);
#endregion
_fftSpectrumAvailable = true;
}
if (_iqStream.Length <= _maxIQSamples)
{
_fftBufferIsWaiting = true;
_fftEvent.WaitOne();
}
}
_iqStream.Flush();
}
private void CalculatePower(Complex *buffer, int pos, int length)
{
var fftSize = NextPowerOfTwo(length);
if (_window == null || _window.Length != fftSize)
{
_window = FilterBuilder.MakeWindow(WindowType.Hamming, fftSize);
}
if (_workingBuffer == null || _workingBuffer.Length != fftSize)
{
_workingBuffer = new Complex[fftSize];
_powerSpectrumPanel.PointsPerSecond = (ulong)(_sampleRate / length + 0.5);
}
for (int n = 0; n < fftSize; n++)
{
if (n < length)
{
_workingBuffer[n] = buffer[pos + n];
}
else
{
_workingBuffer[n] = 0;
}
}
fixed(Complex *workingPtr = &_workingBuffer[0])
{
fixed(float *winPtr = &_window[0])
Fourier.ApplyFFTWindow(workingPtr, winPtr, fftSize);
Fourier.ForwardTransform(workingPtr, fftSize);
}
var herzPerBin = _sampleRate / fftSize;
var offsetHerz = MainControl.Frequency - MainControl.CenterFrequency;
var offsetBins = (int)(offsetHerz / herzPerBin + 0.5);
var freqBinIndex = fftSize / 2 + offsetBins;
var avgInBins = (int)(MainControl.FilterBandwidth / herzPerBin + 0.5);
if (avgInBins == 0)
{
avgInBins = 1;
}
int startIndex;
int endIndex;
switch (MainControl.DetectorType)
{
case DetectorType.LSB:
startIndex = freqBinIndex - avgInBins;
endIndex = freqBinIndex;
break;
case DetectorType.USB:
startIndex = freqBinIndex;
endIndex = freqBinIndex + avgInBins;
break;
default:
startIndex = (int)(freqBinIndex - avgInBins / 2.0f + 0.5);
endIndex = (int)(freqBinIndex + avgInBins / 2.0f + 0.5);
break;
}
if (startIndex < 0)
{
startIndex = 0;
}
if (endIndex >= _workingBuffer.Length)
{
endIndex = _workingBuffer.Length;
}
var totalPower = 0.0f;
for (var n = startIndex; n < endIndex; n++)
{
//CheckMinMax(_workingBuffer[n]);
totalPower += (float)(10.0 * Math.Log10(1e-60 + (_workingBuffer[n].Real * _workingBuffer[n].Real + _workingBuffer[n].Imag * _workingBuffer[n].Imag)));
}
var fftGain = (float)(10.0 * Math.Log10(fftSize / 2.0));
var compensation = 24.0f - fftGain - 40.0f;
var dataPointValue = totalPower / avgInBins + compensation;
if (dataPointValue >= _controlPanel.SquelchValue)
{
_powerTriggerCount++;
}
else
{
_powerTriggerCount = 0;
}
SquelchOpen = _powerTriggerCount > 1;
if (_powerSpectrumPanel.Visible)
{
_powerSpectrumPanel.Draw(dataPointValue);
}
}
public void Process(Complex *buffer, int length)
{
if (!_scanning)
{
return;
}
if (_control.Frequency == _checkedFrequency)
{
return;
}
if (_workingBuffer == null || _workingBuffer.Length < length)
{
_workingBuffer = new Complex[length];
}
for (var n = 0; n < length; n++)
{
_workingBuffer[n] = buffer[n];
}
if (_window == null || _window.Length < length)
_window = FilterBuilder.MakeWindow(WindowType.Hamming, length);
fixed(Complex *workingPtr = &_workingBuffer[0])
{
fixed(float *winPtr = &_window[0])
Fourier.ApplyFFTWindow(workingPtr, winPtr, length);
Fourier.ForwardTransform(workingPtr, length);
if (_spectrum == null || _spectrum.Length < length)
_spectrum = new float[length];
fixed(float *spectrumPtr = &_spectrum[0])
Fourier.SpectrumPower(workingPtr, spectrumPtr, length);
}
float avg = 0.0f;
for (var n = 0; n < length; n++)
{
avg += _spectrum[n];
}
avg /= length;
_drawing.AddDataPoint(_control.Frequency, avg);
if (_control.Frequency > _gui.EndFreq * 1000000 - _gui.Step * 1000)
{
StopScanning();
}
else
{
if (_control.IsPlaying)
{
_checkedFrequency = _control.Frequency;
_control.SetFrequency(_control.Frequency + _gui.Step * 1000, false);
}
}
}
