public void Calculate(double[] input)
{
int count = (int)pCount.data;
if (averagingType == AveragingType.Linear || count < numberOfAverages)
{
alpha = (double)count / (count + 1);
}
else
{
alpha = 1 - 2.0 / (numberOfAverages + 1);
}
beta = 1 - alpha;
for (int i = 0; i < input.Length; i++)
{
timeSignal[i] = input[i];
temp[i].re = input[i] * hanning[i];
temp[i].im = 0;
}
fft.FftForward(temp);
for (int i = 0; i < temp.Length; i++)
{
instSpectrum[i] = temp[i];
}
for (int i = 0; i < autoSpectrumLength; i++)
{
double power = Complex.AbsSqr(temp[i]) * factor;
if (i == 0)
{
power *= 0.5;
}
autoSpectrum[i] = autoSpectrum[i] * alpha + power * beta;
}
int N = temp.Length;
for (int i = 0; i < N; i++)
{
temp[i] = new Complex(0, 0);
}
for (int i = 0; i < autoSpectrum.Length; i++)
{
temp[i].re = Math.Sqrt(autoSpectrum[i]);
}
double min = double.MaxValue;
for (int i = 0; i <= N / 2; i++)
{
if (temp[i].re > 0 && temp[i].re < min)
{
min = temp[i].re;
}
}
for (int i = 0; i <= N / 2; i++)
{
if (temp[i].re == 0)
{
temp[i].re = min;
}
}
for (int i = 0; i <= N / 2; i++)
{
temp[i].re = 2 * Math.Log(temp[i].re);
}
//int n0 = (int)(20.0 / 51200 * N);
//for (int i = 0; i <= n0; i++)
// temp[i].re *= 0.5 * (1 - Math.Cos(Math.PI / n0 * i));
//int n2 = (int)(10000.0 / 51200 * N);
//for (int i = n2; i <= N / 2; i++)
// temp[i].re *= 0.5 * (1 + Math.Cos(Math.PI / (N / 2 - n2) * (i - n2)));
for (int i = 1; i < N / 2; i++)
{
temp[N - i].re = temp[i].re;
}
fft.FftInverse(temp);
int n3 = N / 2 + 1;
int n4 = N / 2 + 1;
for (int i = n3; i < n4; i++)
{
temp[i] *= 0.5 * (1 + Math.Cos(Math.PI / (n4 - n3) * (i - n3)));
}
for (int i = n4; i < N; i++)
{
temp[i] = new Complex(0, 0);
}
n4 = 1;
for (int i = 0; i < n4; i++)
{
double fact = 0.5 * (1 + Math.Sin(Math.PI / 2 / n4 * i));
temp[i] *= fact;
temp[N / 2 - i] *= fact;
}
fft.FftForward(temp);
for (int i = 0; i < N / 2; i++)
{
temp[i] = Math.Exp(temp[i].re) * new Complex(Math.Cos(temp[i].im), Math.Sin(temp[i].im));
temp[i + N / 2] = new Complex(0, 0);
}
//for (int i = 0; i <= n0; i++)
// temp[i] = new Complex(0, 0);
//for (int i = n2; i < N; i++)
// temp[i] = new Complex(0, 0);
fft.FftInverse(temp);
int skip = (int)(0.005 * 51200);
double max = double.MinValue;
for (int i = skip; i < N; i++)
{
if (Math.Abs(temp[i].re) > max)
{
max = Math.Abs(temp[i].re);
}
}
double factor1 = 30000 / max;
for (int i = skip; i < N; i++)
{
temp[i - skip] = temp[i] * factor1;
}
for (int i = N - skip; i < N; i++)
{
temp[i] = new Complex(0, 0);
}
for (int i = 0; i < N / 2; i++)
{
autocorrelation[i] = (autocorrelation[i] * count + temp[i].re) / (count + 1);
}
count++;
if (false)
{
WaveIO waveIO = new WaveIO();
waveIO.SamplingFrequency = 51200;
waveIO.SaveRealData("c:/users/jhee/impavg.wav", autocorrelation, 1);
}
pCount.data = count;
}
