first version of CPM code

10 files changed, 680 insertions, 5 deletions

diff --git a/gnuradio-core/src/lib/hier/Makefile.am b/gnuradio-core/src/lib/hier/Makefile.am
index e2e7fe886..3a7c9f592 100644
--- a/gnuradio-core/src/lib/hier/Makefile.am
+++ b/gnuradio-core/src/lib/hier/Makefile.am
@@ -1,5 +1,5 @@
 #
-# Copyright 2009 Free Software Foundation, Inc.
+# Copyright 2009,2010 Free Software Foundation, Inc.
 # 
 # This file is part of GNU Radio
 # 
@@ -24,16 +24,32 @@ include $(top_srcdir)/Makefile.common
 
 AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(WITH_INCLUDES)
 
-noinst_LTLIBRARIES = libhier.la
+noinst_LTLIBRARIES = libhier.la libhier-qa.la
 
 libhier_la_SOURCES = \
-	gr_channel_model.cc
+	gr_channel_model.cc \
+	gr_cpm.cc \
+	gr_cpmmod_bc.cc
 
 grinclude_HEADERS = \
-	gr_channel_model.h
+	gr_channel_model.h \
+	gr_cpm.h \
+	gr_cpmmod_bc.h
+
 
 if PYTHON
 swiginclude_HEADERS = \
 	hier.i \
-	gr_channel_model.i
+	gr_channel_model.i \
+	gr_cpmmod_bc.i \
+	gr_cpm.i
 endif
+
+
+libhier_qa_la_SOURCES = \
+	qa_gr_cpm.cc
+
+noinst_HEADERS = \
+	qa_gr_cpm.h
+
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpm.cc b/gnuradio-core/src/lib/hier/gr_cpm.cc
new file mode 100644
index 000000000..5eda182b2
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpm.cc
@@ -0,0 +1,210 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+// Calculate the taps for the CPM phase responses
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <cmath>
+#include <cfloat>
+#include <gr_cpm.h>
+
+
+//! Normalised sinc function, sinc(x)=sin(pi*x)/pi*x
+inline double
+sinc(double x)
+{
+	if (x == 0) {
+		return 1.0;
+	}
+
+	return sin(M_PI * x) / (M_PI * x);
+}
+
+
+//! Taps for L-RC CPM (Raised cosine of length L symbols)
+std::vector<float>
+generate_cpm_lrc_taps(unsigned samples_per_sym, unsigned L)
+{
+	std::vector<float> taps(samples_per_sym * L, 1.0/L/samples_per_sym);
+	for (int i = 0; i < samples_per_sym * L; i++) {
+		taps[i] *= 1 - cos(M_TWOPI * i / L / samples_per_sym);
+	}
+
+	return taps;
+}
+
+
+/*! Taps for L-SRC CPM (Spectral raised cosine of length L symbols).
+ *
+ * L-SRC has a time-continuous phase response function of
+ *
+ * g(t) = 1/LT * sinc(2t/LT) * cos(beta * 2pi t / LT) / (1 - (4beta / LT * t)^2)
+ *
+ * which is the Fourier transform of a cos-rolloff function with rolloff
+ * beta, and looks like a sinc-function, multiplied with a rolloff term.
+ * We return the main lobe of the sinc, i.e., everything between the
+ * zero crossings.
+ * The time-discrete IR is thus
+ *
+ * g(k) = 1/Ls * sinc(2k/Ls) * cos(beta * pi k / Ls) / (1 - (4beta / Ls * k)^2)
+ * where k = 0...Ls-1
+ * and s = samples per symbol.
+ */
+std::vector<float>
+generate_cpm_lsrc_taps(unsigned samples_per_sym, unsigned L, double beta)
+{
+	double Ls = (double) L * samples_per_sym;
+	std::vector<double> taps_d(Ls, 0.0);
+	std::vector<float> taps(Ls, 0.0);
+
+	for (int i = 0; i < samples_per_sym * L; i++) {
+		double k =  i - Ls/2; // Causal to acausal
+
+		taps_d[i] = 1.0 / Ls * sinc(2.0 * k / Ls);
+
+		// For k = +/-Ls/4*beta, the rolloff term's cos-function becomes zero
+		// and the whole thing converges to PI/4 (to prove this, use de
+		// l'hopital's rule).
+		if (fabs(abs(k) - Ls/4/beta) < 2*DBL_EPSILON) {
+			taps_d[i] *= M_PI_4;
+		} else {
+			double tmp = 4.0 * beta * k / Ls;
+			taps_d[i] *= cos(beta * M_TWOPI * k / Ls) / (1 - tmp * tmp);
+		}
+		sum += taps_d[i];
+	}
+	for (int i = 0; i < samples_per_sym * L; i++) {
+		taps[i] = (float) taps_d[i] / sum;
+	}
+
+	return taps;
+}
+
+
+//! Taps for L-REC CPM (Rectangular pulse shape of length L symbols)
+std::vector<float>
+generate_cpm_lrec_taps(unsigned samples_per_sym, unsigned L)
+{
+	return std::vector<float>(samples_per_sym * L, 1.0/L/samples_per_sym);
+}
+
+
+//! Helper function for TFM
+double tfm_g0(double k, double sps)
+{
+	if (k < 2 * DBL_EPSILON) {
+		return 1.145393004159143; // 1 + pi^2/48 / sqrt(2)
+	}
+
+	const double pi2_24 = 0.411233516712057; // pi^2/24
+	double f = M_PI * k / sps;
+	return sinc(k/sps) - pi2_24 * (2 * sin(f) - 2*f*cos(f) - f*f*sin(f)) / (f*f*f);
+}
+
+
+//! Taps for TFM CPM (Tamed frequency modulation)
+//
+// See [2, Chapter 2.7.2].
+//
+// [2]: Anderson, Aulin and Sundberg; Digital Phase Modulation
+std::vector<float>
+generate_cpm_tfm_taps(unsigned sps, unsigned L)
+{
+	double causal_shift = (double) L * sps / 2;
+	std::vector<double> taps_d(Ls, 0.0);
+	std::vector<float> taps(Ls, 0.0);
+
+	double sum = 0;
+	for (int i = 0; i < sps * L; i++) {
+		double k = (double)i - causal_shift; // Causal to acausal
+
+		taps_d[i] =     tfm_g0(k - sps, sps) +
+		            2 * tfm_g0(k,       sps) +
+		                tfm_g0(k + sps, sps);
+		sum += taps_d[i];
+	}
+	for (int i = 0; i < samples_per_sym * L; i++) {
+		taps[i] = (float) taps_d[i] / sum;
+	}
+
+	return taps;
+}
+
+
+//! Taps for Gaussian CPM. Phase response is truncated after \p L symbols.
+//  \p bt sets the 3dB-time-bandwidth product.
+//
+// Note: for h = 0.5, this is the phase response for GMSK.
+//
+// This C99-compatible formula for the taps is taken straight
+// from [1, Chapter 9.2.3].
+// A version in Q-notation can be found in [2, Chapter 2.7.2].
+//
+// [1]: Karl-Dirk Kammeyer; Nachrichtenübertragung, 4th Edition.
+// [2]: Anderson, Aulin and Sundberg; Digital Phase Modulation
+//
+std::vector<float>
+generate_cpm_gaussian_taps(unsigned samples_per_sym, unsigned L, double bt)
+{
+	double Ls = (double) L * samples_per_sym;
+	std::vector<double> taps_d(Ls, 0.0);
+	std::vector<float> taps(Ls, 0.0);
+
+	// alpha = sqrt(2/ln(2)) * pi * BT
+	double alpha = 5.336446256636997 * bt;
+	for (int i = 0; i < samples_per_sym * L; i++) {
+		double k =  i - Ls/2; // Causal to acausal
+		taps_d[i] = (erf(alpha * (k / samples_per_sym + 0.5)) -
+		             erf(alpha * (k / samples_per_sym - 0.5)))
+			        * 0.5 / samples_per_sym;
+		taps[i] = (float) taps_d[i];
+	}
+
+	return taps;
+}
+
+
+std::vector<float>
+gr_cpm::phase_response(cpm_type type, unsigned samples_per_sym, unsigned L, double beta)
+{
+	switch (type) {
+		case LRC:
+			return generate_cpm_lrc_taps(samples_per_sym, L);
+
+		case LSRC:
+			return generate_cpm_lsrc_taps(samples_per_sym, L, beta);
+
+		case LREC:
+			return generate_cpm_lrec_taps(samples_per_sym, L);
+
+		case TFM:
+			return generate_cpm_tfm_taps(samples_per_sym, L);
+
+		case GAUSSIAN:
+			return generate_cpm_gaussian_taps(samples_per_sym, L, beta);
+
+		default:
+			return generate_cpm_lrec_taps(samples_per_sym, 1);
+	}
+}
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpm.h b/gnuradio-core/src/lib/hier/gr_cpm.h
new file mode 100644
index 000000000..f32fa44fd
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpm.h
@@ -0,0 +1,75 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+
+#ifndef INCLUDED_GR_CPM_H
+#define INCLUDED_GR_CPM_H
+
+#define M_TWOPI (2*M_PI)
+
+class gr_cpm
+{
+ public:
+	enum cpm_type {
+	 LRC,
+	 LSRC,
+	 LREC,
+	 TFM,
+	 GAUSSIAN,
+	 GENERIC = 999
+	};
+
+	//! Return the taps for an interpolating FIR filter (gr_fir_filter_fff).
+	//
+	// These taps represent the phase response for use in a CPM modulator.
+	//
+	// Parameters:
+	// \p type: The CPM type (Rectangular, Raised Cosine, Spectral Raised Cosine,
+	//          Tamed FM or Gaussian).
+	// \p samples_per_sym: Samples per symbol.
+	// \p L: The length of the phase response in symbols.
+	// \p beta: For Spectral Raised Cosine, this is the rolloff factor. For Gaussian
+	//          phase responses, this the 3dB-time-bandwidth product. For all other
+	//          cases, it is ignored.
+	//
+	// Output: returns a vector of length \p L * \p samples_per_sym. This can be used
+	//         directly in an interpolating FIR filter such as gr_interp_fir_filter_fff
+	//         with interpolation factor \p samples_per_sym.
+	//
+	// All taps are normalised s.t. \sum taps = 1; this causes a maximum phase change
+	// of h*pi between two symbols, where h is the modulation index.
+	//
+	// The following phase responses can be generated:
+	// * LREC: Rectangular phase response.
+	// * LRC: Raised cosine phase response, looks like 1 - cos(x).
+	// * LSRC: Spectral raised cosine. This requires a rolloff factor beta.
+	//         The phase response is the Fourier transform of raised cosine
+	//         function.
+	// * TFM: Tamed frequency modulation. This scheme minimizes phase change for
+	//        rapidly varying input symbols.
+	// * GAUSSIAN: A Gaussian phase response. For a modulation index h = 1/2, this
+	//             results in GMSK.
+	//
+	static std::vector<float>
+	phase_response(cpm_type type, unsigned samples_per_sym, unsigned L, double beta=0.3);
+};
+
+#endif /* INCLUDED_GR_CPM_H */
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpm.i b/gnuradio-core/src/lib/hier/gr_cpm.i
new file mode 100644
index 000000000..7145f5edd
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpm.i
@@ -0,0 +1,40 @@
+/* -*- C++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+%rename(cpm) gr_cpm;
+
+class gr_cpm
+{
+ public:
+	enum cpm_type {
+	 LRC,
+	 LSRC,
+	 LREC,
+	 TFM,
+	 GAUSSIAN,
+	 GENERIC = 999
+	};
+
+	std::vector<float>
+	phase_response(cpm_type type, unsigned samples_per_sym, unsigned L, double beta=0.3);
+};
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpmmod_bc.cc b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.cc
new file mode 100644
index 000000000..8f9d30cda
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.cc
@@ -0,0 +1,74 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gri_cpm.h>
+#include <gr_cpmmod_bc.h>
+#include <gr_io_signature.h>
+
+
+// Shared pointer constructor
+gr_cpmmod_bc_sptr
+gr_make_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta)
+{
+  return gnuradio::get_initial_sptr(new gr_cpmmod_bc((cpm_type)type, h, samples_per_sym, L, beta));
+}
+
+
+// Parameters:
+// - type (raised cosine, spectral raised cosine, rectangular, tamed fm, gmsk.
+// - h (modulation index)
+// - L (length of filter in symbols)
+// - samples per symbol
+// - beta (for gmsk: BT product, for the RC's: rolloff)
+gr_cpmmod_bc::gr_cpmmod_bc(cpm_type type, double h, unsigned samples_per_sym,
+							unsigned L, double beta)
+  : gr_hier_block2("gr_cpmmod_bc",
+		   gr_make_io_signature(1, 1, sizeof(char)),
+		   gr_make_io_signature2(1, 2, sizeof(gr_complex), sizeof(float))),
+	d_char_to_float(gr_make_char_to_float()),
+	d_fm(gr_make_frequency_modulator_fc(M_TWOPI * h / samples_per_sym)),
+	d_taps(generate_cpm_taps(type, samples_per_sym, L, beta)),
+	d_pulse_shaper(gr_make_interp_fir_filter_fff(samples_per_sym, d_taps))
+{
+  switch (type) {
+	  case CPM_LRC:
+	  case CPM_LSRC:
+	  case CPM_LREC:
+	  case CPM_TFM:
+	  case CPM_GMSK:
+		  break;
+
+	  default:
+		  throw std::invalid_argument("invalid CPM type");
+  }
+
+  connect(self(), 0, d_char_to_float, 0);
+  connect(d_char_to_float, 0, d_pulse_shaper, 0);
+  connect(d_pulse_shaper, 0, d_fm, 0);
+  connect(d_fm, 0, self(), 0);
+
+  // FIXME is this valid? multiple outputs?
+  connect(d_pulse_shaper, 0, self(), 1);
+}
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpmmod_bc.h b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.h
new file mode 100644
index 000000000..ac96a2d85
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.h
@@ -0,0 +1,62 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <gr_top_block.h>
+#include <gr_char_to_float.h>
+#include <gr_interp_fir_filter_fff.h>
+#include <gr_frequency_modulator_fc.h>
+
+
+class gr_cpmmod_bc;
+typedef boost::shared_ptr<gr_cpmmod_bc> gr_cpmmod_bc_sptr;
+
+enum gr_cpmmod_bc::cpm_type;
+
+gr_cpmmod_bc_sptr
+gr_make_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta=0.3);
+
+/*!
+ * \brief Generic CPM modulator
+ *
+ * \ingroup modulation_blk
+ *
+ * The input of this block are symbols from an M-ary alphabet
+ * \pm1, \pm3, ..., \pm(M-1). Usually, M = 2 and therefore, the
+ * valid inputs are \pm1.
+ * The output is the phase-modulated signal.
+ */
+class gr_cpmmod_bc : public gr_hier_block2
+{
+	friend gr_cpmmod_bc_sptr gr_make_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta);
+	gr_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta);
+
+	gr_char_to_float_sptr d_char_to_float;
+	gr_interp_fir_filter_fff_sptr d_pulse_shaper;
+	gr_frequency_modulator_fc_sptr d_fm;
+
+	std::vector<float> d_taps;
+
+ public:
+	//! Return the phase response FIR taps
+	 std::vector<float> get_taps() { return d_taps; };
+};
+
diff --git a/gnuradio-core/src/lib/hier/gr_cpmmod_bc.i b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.i
new file mode 100644
index 000000000..a474aa4d9
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/gr_cpmmod_bc.i
@@ -0,0 +1,36 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+GR_SWIG_BLOCK_MAGIC(gr, cpmmod_bc)
+
+gr_cpmmod_bc_sptr
+gr_make_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta);
+
+class gr_cpmmod_bc : public gr_hier_block2
+{
+ private:
+  gr_cpmmod_bc(int type, float h, unsigned samples_per_sym, unsigned L, double beta);
+
+ public:
+  std::vector<float> get_taps();
+};
+
diff --git a/gnuradio-core/src/lib/hier/hier.i b/gnuradio-core/src/lib/hier/hier.i
index dbcc8e915..6ac2903fa 100644
--- a/gnuradio-core/src/lib/hier/hier.i
+++ b/gnuradio-core/src/lib/hier/hier.i
@@ -26,6 +26,9 @@
 #endif
 
 #include <gr_channel_model.h>
+#include <gr_cpmmod_bc.h>
 %}
 
 %include "gr_channel_model.i"
+%include "gr_cpmmod_bc.i"
+
diff --git a/gnuradio-core/src/lib/hier/qa_gr_cpm.cc b/gnuradio-core/src/lib/hier/qa_gr_cpm.cc
new file mode 100644
index 000000000..835ff4b28
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/qa_gr_cpm.cc
@@ -0,0 +1,108 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <qa_gr_cpm.h>
+#include <gr_cpm.h>
+#include <cppunit/TestAssert.h>
+
+// Check LREC phase response
+void
+qa_gr_cpm::t1 ()
+{
+	int L = 5;
+	int samples_per_sym = 4;
+	std::vector<float> taps(gr_cpm::phase_response(gr_cpm::LREC, samples_per_sym, L));
+
+	for (int i = 0; i < L * samples_per_sym; i++) {
+		CPPUNIT_ASSERT_DOUBLES_EQUAL(taps[i], 0.05);
+	}
+}
+
+
+// Check LRC phase response
+void
+qa_gr_cpm::t2 ()
+{
+	int L = 5;
+	int samples_per_sym = 4;
+	std::vector<float> taps(gr_cpm::phase_response(gr_cpm::LRC, samples_per_sym, L));
+	float sum = 0;
+
+	for (int i = 0; i < L * samples_per_sym; i++) {
+		sum += taps[i];
+	}
+
+	CPPUNIT_ASSERT_DOUBLES_EQUAL(sum, 1.0);
+	CPPUNIT_ASSERT_DOUBLES_EQUAL(taps[L*samples_per_sym/2], 0.05);
+}
+
+
+// Check LSRC phase response
+void
+qa_gr_cpm::t3 ()
+{
+	int L = 5;
+	int samples_per_sym = 4;
+	std::vector<float> taps(gr_cpm::phase_response(gr_cpm::LSRC, samples_per_sym, L, 0.2));
+	float sum = 0;
+
+	for (int i = 0; i < L * samples_per_sym; i++) {
+		sum += taps[i];
+	}
+
+	CPPUNIT_ASSERT_DOUBLES_EQUAL(sum, 1.0);
+}
+
+
+// Check the TFM phase response
+void
+qa_gr_cpm::t4 ()
+{
+	int L = 5;
+	int samples_per_sym = 4;
+	std::vector<float> taps(gr_cpm::phase_response(gr_cpm::TFM, samples_per_sym, L));
+	float sum = 0;
+
+	for (int i = 0; i < L * samples_per_sym; i++) {
+		sum += taps[i];
+	}
+
+	CPPUNIT_ASSERT_DOUBLES_EQUAL(sum, 1.0);
+}
+
+
+// Check the Gaussian phase response
+void
+qa_gr_cpm::t5 ()
+{
+	int L = 5;
+	int samples_per_sym = 4;
+	std::vector<float> taps(gr_cpm::phase_response(gr_cpm::GAUSSIAN, samples_per_sym, L, 0.3));
+	float sum = 0;
+
+	for (int i = 0; i < L * samples_per_sym; i++) {
+		sum += taps[i];
+	}
+
+	CPPUNIT_ASSERT_DOUBLES_EQUAL(sum, 1.0, 1e-4);
+}
+
diff --git a/gnuradio-core/src/lib/hier/qa_gr_cpm.h b/gnuradio-core/src/lib/hier/qa_gr_cpm.h
new file mode 100644
index 000000000..16965593a
--- /dev/null
+++ b/gnuradio-core/src/lib/hier/qa_gr_cpm.h
@@ -0,0 +1,51 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2010 Free Software Foundation, Inc.
+ * 
+ * This file is part of GNU Radio
+ * 
+ * GNU Radio is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ * 
+ * GNU Radio is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with GNU Radio; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+#ifndef _QA_GRI_CPM_H
+#define _QA_GRI_CPM_H
+
+#include <cppunit/extensions/HelperMacros.h>
+#include <cppunit/TestCase.h>
+
+class qa_gri_cpm : public CppUnit::TestCase {
+
+  CPPUNIT_TEST_SUITE (qa_gri_cpm);
+  CPPUNIT_TEST (t1);
+  CPPUNIT_TEST (t2);
+  CPPUNIT_TEST (t3);
+  CPPUNIT_TEST (t4);
+  CPPUNIT_TEST (t5);
+  CPPUNIT_TEST (t6);
+  CPPUNIT_TEST_SUITE_END ();
+
+ private:
+  void t1 ();
+  void t2 ();
+  void t3 ();
+  void t4 ();
+  void t5 ();
+  void t6 ();
+
+};
+
+
+#endif /* _QA_GRI_CPM_H */
+