added low pass filter

app/src/main/java/xdsopl/robot36/Filter.java

@@ -0,0 +1,22 @@
+/*
+FIR Filter
+
+Copyright 2024 Ahmet Inan <xdsopl@gmail.com>
+*/
+
+package xdsopl.robot36;
+
+public final class Filter {
+	public static double sinc(double x) {
+		if (x == 0)
+			return 1;
+		x *= Math.PI;
+		return Math.sin(x) / x;
+	}
+
+	public static double lowPass(double cutoff, int n, int N) {
+		double f = 2 * cutoff;
+		double x = n - (N - 1) / 2.0;
+		return f * sinc(f * x);
+	}
+}