From c7f3cdd565c544c2f28a39baa1bffe38e4cddada Mon Sep 17 00:00:00 2001
From: Ahmet Inan <inan@aicodix.de>
Date: Mon, 25 Feb 2019 13:00:58 +0100
Subject: [PATCH] added normalizer for sinusoidal signal

---
 README.md    |  4 ++++
 normalize.hh | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 normalize.hh

diff --git a/README.md b/README.md
index 5c4ed86..2673637 100644
--- a/README.md
+++ b/README.md
@@ -45,6 +45,10 @@ The following [infinite impulse response](https://en.wikipedia.org/wiki/Infinite
 
 A [notch filter at DC](https://en.wikipedia.org/wiki/Band-stop_filter) helps removing [DC bias](https://en.wikipedia.org/wiki/DC_bias).
 
+### [normalize.hh](normalize.hh)
+
+Normalizers for [periodic](https://en.wikipedia.org/wiki/Periodic_function) signals.
+
 ### [phasor.hh](phasor.hh)
 
 [Numerically controlled oscillator](https://en.wikipedia.org/wiki/Numerically_controlled_oscillator) implemented using a [phasor](https://en.wikipedia.org/wiki/Phasor) and [complex multiplication](https://en.wikipedia.org/wiki/Complex_number#Multiplication) instead of a [lookup table](https://en.wikipedia.org/wiki/Lookup_table).
diff --git a/normalize.hh b/normalize.hh
new file mode 100644
index 0000000..6f939bd
--- /dev/null
+++ b/normalize.hh
@@ -0,0 +1,53 @@
+/*
+Normalizers for periodic signals
+
+Copyright 2019 Ahmet Inan <inan@aicodix.de>
+*/
+
+#pragma once
+
+#include "blockdc.hh"
+#include "ema.hh"
+
+namespace DSP {
+
+template <typename TYPE>
+class NormalizeSine
+{
+	DSP::BlockDC<TYPE, TYPE> hpf;
+	DSP::EMA<TYPE, TYPE> lpf;
+public:
+	constexpr NormalizeSine() : lpf(1)
+	{
+	}
+	void samples(int s)
+	{
+		hpf.samples(s);
+		lpf.samples(s);
+	}
+	TYPE operator()(TYPE input)
+	{
+		TYPE tmp = hpf(input);
+		TYPE amp = sqrt(TYPE(2) * lpf(tmp * tmp));
+		return tmp / amp;
+	}
+};
+
+template <typename COMPLEX>
+class NormalizeIQ
+{
+	NormalizeSine<typename COMPLEX::value_type> ni, nq;
+public:
+	void samples(int s)
+	{
+		ni.samples(s);
+		nq.samples(s);
+	}
+	COMPLEX operator()(COMPLEX iq)
+	{
+		return COMPLEX(ni(iq.real()), nq(iq.imag()));
+	}
+};
+
+}
+