private static void NormalizeWaveform(Waveform waveform)
{
// Normalize the waveform data
float[] magnitudeArray = ComplexSingle.GetMagnitudes(waveform.WaveformData.GetRawData());
float magnitudeMax = magnitudeArray.Max();
WritableBuffer <ComplexSingle> waveformBuffer = waveform.WaveformData.GetWritableBuffer();
for (int i = 0; i < waveformBuffer.Count(); i++)
{
waveformBuffer[i] = ComplexSingle.FromPolar(waveformBuffer[i].Magnitude / magnitudeMax, waveformBuffer[i].Phase);
}
// Calculate PAPR over only the burst length
double burstPowerSum = 0;
int burstSampleCount = 0;
for (int i = 0; i < waveform.BurstStartLocations.Length; i++)
{
int offset = waveform.BurstStartLocations[i];
int count = waveform.BurstStopLocations[i] - offset;
burstSampleCount += count;
foreach (ComplexSingle iqPoint in waveformBuffer.Skip(offset).Take(count))
{
burstPowerSum += iqPoint.Real * iqPoint.Real + iqPoint.Imaginary * iqPoint.Imaginary;
}
}
// RMS = sqrt(1/n*(|x_0|^2+|x_1|^2...|x_n|^2))
// |x_n| = sqrt(i_n^2 + q_n^2) therefore |x_n|^2 = i_n^2 + q_n^2
// RMS Power = v_rms^2 = 1/n*(|x_0|^2+|x_1|^2...|x_n|^2) hence p_rms = p_avg
// averagePower = burstPowerSum / burstSampleCount;
// PAPR (Peak to Average Power Ratio) = Peak Power/Avg Power
// PAPR (dB) = 10*log(Peak Power/Avg Power)
// Since we already scaled the data, the max value is simply 1
// instead of doing waveform.PAPR_dB = 10 * Math.Log10(1 / averagePower) we will save a divide and invert the averagePower calculation
waveform.PAPR_dB = 10 * Math.Log10(burstSampleCount / burstPowerSum);
}