/// <summary>
/// Compute complex analytic signal
/// </summary>
/// <param name="samples">Array of samples</param>
/// <returns>Complex analytic signal</returns>
public ComplexDiscreteSignal AnalyticSignal(double[] samples)
{
var analyticSignal = new ComplexDiscreteSignal(1, samples);
var re = analyticSignal.Real;
var im = analyticSignal.Imag;
_fft.Direct(re, im);
for (var i = 1; i < re.Length / 2; i++)
{
re[i] *= 2;
im[i] *= 2;
}
for (var i = re.Length / 2 + 1; i < re.Length; i++)
{
re[i] = 0.0;
im[i] = 0.0;
}
_fft.Inverse(re, im);
return(analyticSignal);
}
/// <summary>
/// Does Fast Hilbert Transform.
/// </summary>
/// <param name="input">Input data</param>
/// <param name="output">Output data</param>
public void Direct(double[] input, double[] output)
{
// just here, for code brevity, use alias _im for output (i.e. it's not internal _im)
var _im = output;
Array.Clear(_re, 0, _re.Length);
Array.Clear(_im, 0, _im.Length);
input.FastCopyTo(_re, input.Length);
_fft.Direct(_re, _im);
for (var i = 1; i < _re.Length / 2; i++)
{
_re[i] *= 2;
_im[i] *= 2;
}
for (var i = _re.Length / 2 + 1; i < _re.Length; i++)
{
_re[i] = 0.0f;
_im[i] = 0.0f;
}
_fft.Inverse(_re, _im);
}
/// <summary>
/// Compute complex analytic signal, double precision
/// </summary>
/// <param name="samples">Array of samples</param>
/// <param name="norm">Normalize by fft size</param>
/// <returns>Complex analytic signal</returns>
public ComplexDiscreteSignal AnalyticSignal(double[] samples, bool norm = true)
{
var analyticSignal = new ComplexDiscreteSignal(1, samples);
var re = analyticSignal.Real;
var im = analyticSignal.Imag;
_fft64.Direct(re, im);
for (var i = 1; i < re.Length / 2; i++)
{
re[i] *= 2;
im[i] *= 2;
}
for (var i = re.Length / 2 + 1; i < re.Length; i++)
{
re[i] = 0.0;
im[i] = 0.0;
}
_fft64.Inverse(re, im);
if (norm)
{
analyticSignal.Attenuate(re.Length);
}
return(analyticSignal);
}