init

DataPRO/FftSharp/Windows/Blackman.cs

@@ -0,0 +1,29 @@
+using System;
+
+namespace FftSharp.Windows
+{
+    public class Blackman : Window, IWindow
+    {
+        private readonly double A = 0.42659071;
+        private readonly double B = 0.49656062;
+        private readonly double C = 0.07684867;
+
+        public override string Name => "Blackman";
+        public override string Description =>
+            "These exact values place zeros at the third and fourth sidelobes, " +
+            "but result in a discontinuity at the edges and a 6 dB/oct fall-off. " +
+            "The truncated coefficients do not null the sidelobes as well, but have an improved 18 dB/oct fall-off.";
+
+        public Blackman() { }
+
+        public Blackman(double a, double b, double c) : this()
+        {
+            (A, B, C) = (a, b, c);
+        }
+
+        protected override double windowValue(int index, int size)
+        {
+            return A - B * Math.Cos(2 * Math.PI * index / size) + C * Math.Cos(4 * Math.PI * index / size);
+        }
+    }
+}