From 842b2fad60d809ab447e2774a94c61fdc3134b4a Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Sat, 20 Dec 2014 20:55:42 +0000
Subject: [PATCH] - initial version

git-svn-id: http://moon:8086/svn/software/trunk/libsrc/cpp@93 b431acfa-c32f-4a4a-93f1-934dc6c82436
---
 radio/Interpolation.hpp | 168 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 168 insertions(+)
 create mode 100644 radio/Interpolation.hpp

diff --git a/radio/Interpolation.hpp b/radio/Interpolation.hpp
new file mode 100644
index 0000000..e9d830e
--- /dev/null
+++ b/radio/Interpolation.hpp
@@ -0,0 +1,168 @@
+/* 
+ * File:   Interpolation.hpp
+ * Author: jens
+ *
+ * Created on 20. Dezember 2014, 19:02
+ */
+
+#ifndef INTERPOLATION_HPP
+#define	INTERPOLATION_HPP
+
+#include <cstdio>
+#include "Vector.hpp"
+#include "FirComplex.hpp"
+
+namespace Radio
+{
+namespace Interpolation
+{
+
+class Farrow : public FirComplex
+{
+	typedef struct _ml_farrow_coef_hdr_t
+	{
+		uint32_t M;
+		uint32_t N;
+	} ml_farrow_coef_hdr_t;
+	
+public:
+	Farrow(uint32_t M=0, uint32_t N=0)
+	: FirComplex(N)
+	, m_M(M)
+	, m_N(N)
+	, m_w(0)
+	, m_r(0)
+	, m_coeff(N, M)
+	, m_b(M)
+	, m_h(M)
+	, m_fifo(N)
+	{
+		init(M, N);
+	}
+	
+	~Farrow()
+	{
+		
+	}
+	
+	void init(uint32_t M, uint32_t N)
+	{
+		FirComplex::setNumTaps(N);
+		m_M = M;
+		m_N = N;
+		m_coeff.resize(N, M);
+		m_b.resize(M);
+		m_h.resize(M);
+		m_fifo.resize(N);
+		m_fifo.setZero();
+	}
+
+	void feed(ComplexScalar const &x, uint32_t push)
+	{
+		m_w = (m_w + push) % m_N;
+		m_fifo[m_w] = x;
+	}
+	
+	ComplexScalar process(radio_float_t mu, uint32_t pop)
+	{
+		uint32_t i, r;
+		int32_t j;
+
+		m_r = (m_r + pop) % m_N;
+
+		if (pop)
+		{
+			r = m_r;
+			j = m_N-1;
+			while(r < m_N)
+			{
+				m_x[j--] = m_fifo[r++];
+			}
+			r = 0;
+			while(j >= 0)
+			{
+				m_x[j--] = m_fifo[r++];
+			}
+		}
+
+		// Partial filter responses
+		for (i=0; i < m_M; i++)
+		{
+			m_h[i] = FirComplex::processReal(m_coeff.col(i));
+		}
+
+		// Combine
+		return horner(mu);
+	}	
+
+	void load(const char *pFilename)
+	{
+		int i, j;
+		FILE *pFile;
+		ml_farrow_coef_hdr_t hdr;
+		RealScalar *pCoeff;
+		
+		pFile = fopen(pFilename, "rb");
+		if (!pFile)
+		{
+			printf("Can't open %s\n", pFilename);
+			return;
+		}
+		if (EOF == fread(&hdr, sizeof(hdr), 1, pFile))
+		{
+			printf("Can't read %s\n", pFilename);
+			return;
+		}
+
+		init(hdr.M, hdr.N);
+
+		pCoeff = new RealScalar[hdr.M*hdr.N];
+		for (i=0; i < (int)hdr.M; i++)
+		{
+			if (EOF == fread(pCoeff, sizeof(RealScalar), hdr.N, pFile))
+			{
+				printf("Can't read %s\n", pFilename);
+				return;
+			}
+				
+			for (j=0; j < hdr.N; j++)
+			{
+				m_coeff(j,i) = pCoeff[j];
+			}
+		}
+		printf("Farrow filter coefficients loaded (M=%d, N=%d)", m_M, m_N);
+	
+		delete [] pCoeff;
+
+	}
+	
+private:
+	uint32_t m_M;
+	uint32_t m_N;
+	uint32_t m_r;
+	uint32_t m_w;
+	RMat m_coeff;
+	CVec m_b;
+	CVec m_h;
+	CVec m_fifo;
+	
+	ComplexScalar horner(radio_float_t mu)
+	{
+		uint32_t i;
+
+		m_b[0] = m_h[0];
+		for (i=1; i < m_M; i++)
+		{
+			m_b[i] = ComplexScalar(m_h[i].real() + m_b[i-1].real() * mu, m_h[i].imag() + m_b[i-1].imag() * mu);
+		}
+		
+		return m_b[m_M-1];
+	}
+	
+};
+
+} // Radio::Interpolation
+} // ::Radio
+
+#endif	/* INTERPOLATION_HPP */
+