SignalUtils.BlackmanOptimal Function

Optimal Blackman window.

Pascal

function BlackmanOptimal(const Src: TVec; Index: integer = 0; Len: integer = -1): TVec; overload;

File

SignalUtils

Description

Applies optimal Blackman window to Src. Window functions are applied to the signal prior to conversion to frequency domain with the FFT algorithm, to reduce the spectral leakage. Their side-effect is a lower frequency resolution. The following function defines the Blackman window:

        alpha + 1            2*Pi*n       alpha        4*Pi*n
w[n] = ---------- - 0.5*cos --------  -  ------ * cos(-------)
           2                 n - 1          2          n - 1

            sin(Pi/(n-1))
alpha = - (---------------)^2
           sin(2*Pi/(n-1))