private void Configure()
{
_osc->SampleRate = _sampleRate;
_osc->Frequency = PllDefaultFrequency;
var decimationStageCount = 0;
while (_sampleRate >= 20000 * Math.Pow(2.0, decimationStageCount))
{
decimationStageCount++;
}
_decimator = new IQDecimator(decimationStageCount, _sampleRate, true, false);
_decimationFactor = (int)Math.Pow(2.0, decimationStageCount);
_demodulationSampleRate = _sampleRate / _decimationFactor;
var coefficients = FilterBuilder.MakeLowPassKernel(_demodulationSampleRate, 200, 2500, WindowType.BlackmanHarris4);
_baseBandFilter.SetCoefficients(coefficients);
_pll->SampleRate = (float)_demodulationSampleRate;
_pll->DefaultFrequency = 0;
_pll->Range = PllRange;
_pll->Bandwidth = PllBandwith;
_pll->Zeta = PllZeta;
_pll->LockTime = PllLockTime;
_pll->LockThreshold = PllLockThreshold;
var matchedFilterLength = (int)(_demodulationSampleRate / RdsBitRate) | 1;
coefficients = FilterBuilder.MakeSin(_demodulationSampleRate, RdsBitRate, matchedFilterLength);
_matchedFilter.SetCoefficients(coefficients);
_syncFilter->Init(IirFilterType.BandPass, RdsBitRate, _demodulationSampleRate, 500);
}
private void InitFilters()
{
int cutoff1 = 0;
int cutoff2 = 10000;
var iqBW = _bandwidth / 2;
int iqOrder = _actualDetectorType == DetectorType.WFM ? 60 : _filterOrder;
var coeffs = FilterBuilder.MakeLowPassKernel(_sampleRate / (1 << _baseBandDecimationStageCount), iqOrder, iqBW, _windowType);
if (_iqFilter == null || _decimationModeHasChanged)
{
_iqFilter = new IQFirFilter(coeffs, _actualDetectorType == DetectorType.WFM, 1);
}
else
{
_iqFilter.SetCoefficients(coeffs);
}
switch (_actualDetectorType)
{
case DetectorType.AM:
cutoff1 = MinBCAudioFrequency;
cutoff2 = Math.Min(_bandwidth / 2, MaxBCAudioFrequency);
break;
case DetectorType.CW:
cutoff1 = Math.Abs(_cwToneShift) - _bandwidth / 2;
cutoff2 = Math.Abs(_cwToneShift) + _bandwidth / 2;
break;
case DetectorType.USB:
case DetectorType.LSB:
cutoff1 = MinSSBAudioFrequency;
cutoff2 = _bandwidth;
break;
case DetectorType.DSB:
cutoff1 = MinSSBAudioFrequency;
cutoff2 = _bandwidth / 2;
break;
case DetectorType.NFM:
cutoff1 = MinNFMAudioFrequency;
cutoff2 = _bandwidth / 2;
break;
}
coeffs = FilterBuilder.MakeBandPassKernel(_sampleRate / (1 << (_baseBandDecimationStageCount + _audioDecimationStageCount)), _filterOrder, cutoff1, cutoff2, _windowType);
_audioFilter.SetCoefficients(coeffs);
}
