preEmphasis method

List<double> preEmphasis (
  1. List<num> signal,
  2. double emphasisFactor,
  3. {num lastValue: 0.0}
)

Apply preEmphasis filter on given signal.

Implementation

static List<double> preEmphasis(List<num> signal, double emphasisFactor, {num lastValue = 0.0})  {
  var empSignal = List<double>(signal.length);
  var swSig = [lastValue] + signal.sublist(0, signal.length - 1);
  for (var i =0; i < signal.length; i++) {
    empSignal[i] = signal[i] - swSig[i] * emphasisFactor;
  }
  return empSignal;
}