flattop function Null safety

Array flattop(
  1. int M,
  2. {bool sym = true}
)

Return a flat top window.

Parameters

  • M : int Number of points in the output window. If zero or less, an empty array is returned.
  • sym : bool, optional When true (default), generates a symmetric window, for use in filter design. When false, generates a periodic window, for use in spectral analysis.

Returns

  • w : Array The window, with the maximum value normalized to 1 (though the value 1 does not appear if M is even and sym is True).

Notes

Flat top windows are used for taking accurate measurements of signal amplitude in the frequency domain, with minimal scalloping error from the center of a frequency bin to its edges, compared to others. This is a 5th-order cosine window, with the 5 terms optimized to make the main lobe maximally flat.

References

  1. "scipy.signal.windows.flattop". https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.windows.flattop.html#scipy.signal.windows.flattop. Retrieved 2019-07-15.

Examples

import 'package:scidart/src/numdart/numdart.dart';
import 'package:scidart/scidart/signal/signal.dart';
var M = 10;
var w = flattop(M);

Implementation

Array flattop(int M, {bool sym = true}) {
  var a =
      Array([0.21557895, 0.41663158, 0.277263158, 0.083578947, 0.006947368]);
  return generalCosine(M, a, sym: sym);
}