public MetricFFTBandEnergy(Graph graph)
: base("Band Energy", graph,
InputPort.CreateMany(
InputPort.Create("in", PortDataType.FFT)),
OutputPort.CreateMany(
OutputPort.Create("out", PortDataType.Value)))
{
_portInp = (FFTInputPort)InputPorts[0];
_portOut = (ValueOutputPort)OutputPorts[0];
}
protected override void FftDataAvailable(FFTInputPort port)
{
Func <double, int> FreqToBin = (f) => (int)(f * _portInp.FFTSize / _buffer.Samplerate);
var leftIndex = FreqToBin(CenterFrequency - Bandwidth / 2) + 1;
var rightIndex = FreqToBin(CenterFrequency + Bandwidth / 2);
if (leftIndex == rightIndex)
{
rightIndex = leftIndex + 1;
}
if (leftIndex < 0)
{
leftIndex = 0;
}
else if (leftIndex > _portInp.FFTSize / 2 - 1)
{
leftIndex = _portInp.FFTSize / 2 - 1;
}
if (rightIndex < 0)
{
rightIndex = 0;
}
else if (rightIndex > _portInp.FFTSize / 2 - 1)
{
rightIndex = _portInp.FFTSize / 2 - 1;
}
while (_portInp.Queue.Length > _buffer.Length)
{
_portInp.Queue.Dequeue(_buffer);
var samples = _buffer.GetSamples();
var sum = 0.0;
for (int i = leftIndex; i < rightIndex; i++)
{
sum += samples[i];
}
_portOut.SendData(new TimeLocatedValue(sum, TimeStamp.Zero()));
}
}
