worked on step-detection

adjusted iir biquad
added biquad-stacking

math/dsp/iir/BiQuadStack.h

@@ -0,0 +1,42 @@
+#ifndef BIQUADSTACK_H
+#define BIQUADSTACK_H
+
+#include <vector>
+#include "BiQuad.h"
+
+namespace IIR {
+
+	template <typename Scalar> class BiQuadStack {
+
+		std::vector<BiQuad<Scalar>> filters;
+
+	public:
+
+		BiQuadStack() {
+			;
+		}
+
+		BiQuadStack(const int num) {
+			filters.resize(num);
+		}
+
+		void resize(const int num) {
+			filters.resize(num);
+		}
+
+		BiQuad<Scalar>& operator [] (const size_t idx) {
+			return filters.at(idx);
+		}
+
+		Scalar filter(Scalar val) {
+			for (BiQuad<Scalar>& bq : filters) {
+				val = bq.filter(val);
+			}
+			return val;
+		}
+
+	};
+
+}
+
+#endif // BIQUADSTACK_H