Merge branch 'tr_master'

13 files changed, 740 insertions, 2 deletions

diff --git a/gnuradio-core/src/lib/filter/Makefile.am b/gnuradio-core/src/lib/filter/Makefile.am
index dee13e239..0314079a2 100644
--- a/gnuradio-core/src/lib/filter/Makefile.am
+++ b/gnuradio-core/src/lib/filter/Makefile.am
@@ -216,7 +216,9 @@ libfilter_la_common_SOURCES = 		\
 	gr_pfb_interpolator_ccf.cc	\
 	gr_pfb_arb_resampler_ccf.cc	\
 	gr_pfb_clock_sync_ccf.cc	\
-	gr_pfb_clock_sync_fff.cc
+	gr_pfb_clock_sync_fff.cc	\
+	gr_dc_blocker_cc.cc		\
+	gr_dc_blocker_ff.cc
 
 libfilter_qa_la_common_SOURCES = 	\
 	qa_filter.cc			\
@@ -306,7 +308,9 @@ grinclude_HEADERS = 			\
 	gr_pfb_interpolator_ccf.h	\
 	gr_pfb_arb_resampler_ccf.h	\
 	gr_pfb_clock_sync_ccf.h		\
-	gr_pfb_clock_sync_fff.h
+	gr_pfb_clock_sync_fff.h		\
+	gr_dc_blocker_cc.h		\
+	gr_dc_blocker_ff.h
 
 noinst_HEADERS = 			\
 	assembly.h			\
@@ -372,6 +376,8 @@ swiginclude_HEADERS =			\
 	gr_pfb_arb_resampler_ccf.i	\
 	gr_pfb_clock_sync_ccf.i		\
 	gr_pfb_clock_sync_fff.i		\
+	gr_dc_blocker_cc.i		\
+	gr_dc_blocker_ff.i		\
 	$(GENERATED_I)
 
 
diff --git a/gnuradio-core/src/lib/filter/filter.i b/gnuradio-core/src/lib/filter/filter.i
index 645607cba..58bb4f0d5 100644
--- a/gnuradio-core/src/lib/filter/filter.i
+++ b/gnuradio-core/src/lib/filter/filter.i
@@ -39,6 +39,8 @@
 #include <gr_pfb_arb_resampler_ccf.h>
 #include <gr_pfb_clock_sync_ccf.h>
 #include <gr_pfb_clock_sync_fff.h>
+#include <gr_dc_blocker_cc.h>
+#include <gr_dc_blocker_ff.h>
 %}
 
 %include "gr_iir_filter_ffd.i"
@@ -62,5 +64,7 @@
 %include "gr_pfb_arb_resampler_ccf.i"
 %include "gr_pfb_clock_sync_ccf.i"
 %include "gr_pfb_clock_sync_fff.i"
+%include "gr_dc_blocker_cc.i"
+%include "gr_dc_blocker_ff.i"
 
 %include "filter_generated.i"
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.cc b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.cc
new file mode 100644
index 000000000..e7d5ced25
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.cc
@@ -0,0 +1,138 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gr_dc_blocker_cc.h>
+#include <gr_io_signature.h>
+#include <cstdio>
+
+moving_averager_c::moving_averager_c(int D)
+  : d_length(D), d_out(0), d_out_d1(0), d_out_d2(0)
+{
+  d_delay_line = std::deque<gr_complex>(d_length-1, gr_complex(0,0));
+}
+
+moving_averager_c::~moving_averager_c()
+{
+}
+
+gr_complex
+moving_averager_c::filter(gr_complex x)
+{
+  d_out_d1 = d_out;
+  d_delay_line.push_back(x);
+  d_out = d_delay_line[0];
+  d_delay_line.pop_front();
+    
+  gr_complex y = x - d_out_d1 + d_out_d2;
+  d_out_d2 = y;
+    
+  return (y / (float)(d_length)); 
+}
+
+
+
+gr_dc_blocker_cc_sptr gr_make_dc_blocker_cc (int D, bool long_form)
+{
+  return gnuradio::get_initial_sptr(new gr_dc_blocker_cc(D, long_form));
+}
+
+
+gr_dc_blocker_cc::gr_dc_blocker_cc (int D, bool long_form)
+  : gr_sync_block ("dc_blocker_cc",
+		   gr_make_io_signature (1, 1, sizeof(gr_complex)),
+		   gr_make_io_signature (1, 1, sizeof(gr_complex))),
+    d_length(D), d_long_form(long_form)
+{
+  if(d_long_form) {
+    d_ma_0 = new moving_averager_c(D);
+    d_ma_1 = new moving_averager_c(D);
+    d_ma_2 = new moving_averager_c(D);
+    d_ma_3 = new moving_averager_c(D);
+    d_delay_line = std::deque<gr_complex>(d_length-1, gr_complex(0,0));
+  }
+  else {
+    d_ma_0 = new moving_averager_c(D);
+    d_ma_1 = new moving_averager_c(D);
+  }
+}
+
+gr_dc_blocker_cc::~gr_dc_blocker_cc()
+{
+  if(d_long_form) {
+    delete d_ma_0;
+    delete d_ma_1;
+    delete d_ma_2;
+    delete d_ma_3;
+  }
+  else {
+    delete d_ma_0;
+    delete d_ma_1;
+  }
+}
+
+int
+gr_dc_blocker_cc::get_group_delay()
+{
+  if(d_long_form)
+    return (2*d_length-2);
+  else
+    return d_length - 1;
+}
+
+int
+gr_dc_blocker_cc::work(int noutput_items,
+		       gr_vector_const_void_star &input_items,
+		       gr_vector_void_star &output_items)
+{
+  const gr_complex *in = (const gr_complex*)input_items[0];
+  gr_complex *out = (gr_complex*)output_items[0];
+
+  if(d_long_form) {
+    gr_complex y1, y2, y3, y4, d;
+    for(int i = 0; i < noutput_items; i++) {
+      y1 = d_ma_0->filter(in[i]);
+      y2 = d_ma_1->filter(y1);
+      y3 = d_ma_2->filter(y2);
+      y4 = d_ma_3->filter(y3);
+
+      d_delay_line.push_back(d_ma_0->delayed_sig());
+      d = d_delay_line[0];
+      d_delay_line.pop_front();
+
+      out[i] = d - y4;
+    }
+  }
+  else {
+    gr_complex y1, y2;
+    for(int i = 0; i < noutput_items; i++) {
+      y1 = d_ma_0->filter(in[i]);
+      y2 = d_ma_1->filter(y1);
+      out[i] = d_ma_0->delayed_sig() - y2;
+    }
+  }
+
+  return noutput_items;
+}
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.h b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.h
new file mode 100644
index 000000000..de9ccc0ea
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.h
@@ -0,0 +1,111 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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 INCLUDED_GR_DC_BLOCKER_CC_H
+#define	INCLUDED_GR_DC_BLOCKER_CC_H
+
+#include <gr_sync_block.h>
+#include <deque>
+
+class gr_dc_blocker_cc;
+typedef boost::shared_ptr<gr_dc_blocker_cc> gr_dc_blocker_cc_sptr;
+gr_dc_blocker_cc_sptr gr_make_dc_blocker_cc (int D=32, bool long_form=true);
+
+/*!
+ * \class gr_dc_blocker_cc
+ * \brief a computationally efficient controllabel DC blocker
+ *
+ * \ingroup filter_blk
+ * 
+ * This block implements a computationally efficient DC blocker that produces
+ * a tigher notch filter around DC for a smaller group delay than an
+ * equivalent FIR filter or using a single pole IIR filter (though the IIR
+ * filter is computationally cheaper).
+ *
+ * The block defaults to using a delay line of length 32 and the long form
+ * of the filter. Optionally, the delay line length can be changed to alter
+ * the width of the DC notch (longer lines will decrease the width).
+ *
+ * The long form of the filter produces a nearly flat response outside of
+ * the notch but at the cost of a group delay of 2D-2.
+ *
+ * The short form of the filter does not have as flat a response in the
+ * passband but has a group delay of only D-1 and is cheaper to compute.
+ *
+ * The theory behind this block can be found in the paper:
+ *
+ *    <B><EM>R. Yates, "DC Blocker Algorithms," IEEE Signal Processing Magazine,
+ *        Mar. 2008, pp 132-134.</EM></B>
+ */
+class moving_averager_c
+{
+public:
+  moving_averager_c(int D);
+  ~moving_averager_c();
+
+  gr_complex filter(gr_complex x);
+  gr_complex delayed_sig() { return d_out; }
+
+private:
+  int d_length;
+  gr_complex d_out, d_out_d1, d_out_d2;
+  std::deque<gr_complex> d_delay_line;
+};
+
+class gr_dc_blocker_cc : public gr_sync_block
+{
+ private:
+  /*!
+   * Build the DC blocker.
+   * \param D          (int) the length of the delay line
+   * \param long_form  (bool) whether to use long (true, default) or short form
+   * \param channel (unsigned integer) Selects the channel to return [default=0].
+   */
+  friend gr_dc_blocker_cc_sptr gr_make_dc_blocker_cc (int D, bool long_form);
+
+  int d_length;
+  bool d_long_form;
+  moving_averager_c *d_ma_0;
+  moving_averager_c *d_ma_1;
+  moving_averager_c *d_ma_2;
+  moving_averager_c *d_ma_3;
+  std::deque<gr_complex> d_delay_line;
+
+  gr_dc_blocker_cc (int D, bool long_form);
+
+public:
+  ~gr_dc_blocker_cc ();
+
+  /*!
+   * Get the blocker's group delay that is based on length of delay lines
+   */
+  int get_group_delay();
+
+  //int set_length(int D);
+  
+  int work (int noutput_items,
+	    gr_vector_const_void_star &input_items,
+	    gr_vector_void_star &output_items);
+};
+
+#endif
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.i b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.i
new file mode 100644
index 000000000..b88fecbde
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_cc.i
@@ -0,0 +1,34 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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,dc_blocker_cc);
+
+gr_dc_blocker_cc_sptr gr_make_dc_blocker_cc (int D=32, bool long_form=true);
+
+class gr_dc_blocker_cc : public gr_sync_block
+{
+ private:
+  gr_dc_blocker_cc (int D, bool long_form);
+
+ public:
+  ~gr_dc_blocker_cc ();
+};
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.cc b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.cc
new file mode 100644
index 000000000..d684bc7e8
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.cc
@@ -0,0 +1,138 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <gr_dc_blocker_ff.h>
+#include <gr_io_signature.h>
+#include <cstdio>
+
+moving_averager_f::moving_averager_f(int D)
+  : d_length(D), d_out(0), d_out_d1(0), d_out_d2(0)
+{
+  d_delay_line = std::deque<float>(d_length-1, 0);
+}
+
+moving_averager_f::~moving_averager_f()
+{
+}
+
+float
+moving_averager_f::filter(float x)
+{
+  d_out_d1 = d_out;
+  d_delay_line.push_back(x);
+  d_out = d_delay_line[0];
+  d_delay_line.pop_front();
+    
+  float y = x - d_out_d1 + d_out_d2;
+  d_out_d2 = y;
+    
+  return (y / (float)(d_length)); 
+}
+
+
+
+gr_dc_blocker_ff_sptr gr_make_dc_blocker_ff (int D, bool long_form)
+{
+  return gnuradio::get_initial_sptr(new gr_dc_blocker_ff(D, long_form));
+}
+
+
+gr_dc_blocker_ff::gr_dc_blocker_ff (int D, bool long_form)
+  : gr_sync_block ("dc_blocker_ff",
+		   gr_make_io_signature (1, 1, sizeof(float)),
+		   gr_make_io_signature (1, 1, sizeof(float))),
+    d_length(D), d_long_form(long_form)
+{
+  if(d_long_form) {
+    d_ma_0 = new moving_averager_f(D);
+    d_ma_1 = new moving_averager_f(D);
+    d_ma_2 = new moving_averager_f(D);
+    d_ma_3 = new moving_averager_f(D);
+    d_delay_line = std::deque<float>(d_length-1, 0);
+  }
+  else {
+    d_ma_0 = new moving_averager_f(D);
+    d_ma_1 = new moving_averager_f(D);
+  }
+}
+
+gr_dc_blocker_ff::~gr_dc_blocker_ff()
+{
+  if(d_long_form) {
+    delete d_ma_0;
+    delete d_ma_1;
+    delete d_ma_2;
+    delete d_ma_3;
+  }
+  else {
+    delete d_ma_0;
+    delete d_ma_1;
+  }
+}
+
+int
+gr_dc_blocker_ff::get_group_delay()
+{
+  if(d_long_form)
+    return (2*d_length-2);
+  else
+    return d_length - 1;
+}
+
+int
+gr_dc_blocker_ff::work(int noutput_items,
+		       gr_vector_const_void_star &input_items,
+		       gr_vector_void_star &output_items)
+{
+  const float *in = (const float*)input_items[0];
+  float *out = (float*)output_items[0];
+
+  if(d_long_form) {
+    float y1, y2, y3, y4, d;
+    for(int i = 0; i < noutput_items; i++) {
+      y1 = d_ma_0->filter(in[i]);
+      y2 = d_ma_1->filter(y1);
+      y3 = d_ma_2->filter(y2);
+      y4 = d_ma_3->filter(y3);
+
+      d_delay_line.push_back(d_ma_0->delayed_sig());
+      d = d_delay_line[0];
+      d_delay_line.pop_front();
+
+      out[i] = d - y4;
+    }
+  }
+  else {
+    float y1, y2;
+    for(int i = 0; i < noutput_items; i++) {
+      y1 = d_ma_0->filter(in[i]);
+      y2 = d_ma_1->filter(y1);
+      out[i] = d_ma_0->delayed_sig() - y2;
+    }
+  }
+
+  return noutput_items;
+}
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.h b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.h
new file mode 100644
index 000000000..b632d81da
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.h
@@ -0,0 +1,111 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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 INCLUDED_GR_DC_BLOCKER_FF_H
+#define	INCLUDED_GR_DC_BLOCKER_FF_H
+
+#include <gr_sync_block.h>
+#include <deque>
+
+class gr_dc_blocker_ff;
+typedef boost::shared_ptr<gr_dc_blocker_ff> gr_dc_blocker_ff_sptr;
+gr_dc_blocker_ff_sptr gr_make_dc_blocker_ff (int D=32, bool long_form=true);
+
+/*!
+ * \class gr_dc_blocker_ff
+ * \brief a computationally efficient controllabel DC blocker
+ *
+ * \ingroup filter_blk
+ * 
+ * This block implements a computationally efficient DC blocker that produces
+ * a tigher notch filter around DC for a smaller group delay than an
+ * equivalent FIR filter or using a single pole IIR filter (though the IIR
+ * filter is computationally cheaper).
+ *
+ * The block defaults to using a delay line of length 32 and the long form
+ * of the filter. Optionally, the delay line length can be changed to alter
+ * the width of the DC notch (longer lines will decrease the width).
+ *
+ * The long form of the filter produces a nearly flat response outside of
+ * the notch but at the cost of a group delay of 2D-2.
+ *
+ * The short form of the filter does not have as flat a response in the
+ * passband but has a group delay of only D-1 and is cheaper to compute.
+ *
+ * The theory behind this block can be found in the paper:
+ *
+ *    <B><EM>R. Yates, "DC Blocker Algorithms," IEEE Signal Processing Magazine,
+ *        Mar. 2008, pp 132-134.</EM></B>
+ */
+class moving_averager_f
+{
+public:
+  moving_averager_f(int D);
+  ~moving_averager_f();
+
+  float filter(float x);
+  float delayed_sig() { return d_out; }
+
+private:
+  int d_length;
+  float d_out, d_out_d1, d_out_d2;
+  std::deque<float> d_delay_line;
+};
+
+class gr_dc_blocker_ff : public gr_sync_block
+{
+ private:
+  /*!
+   * Build the DC blocker.
+   * \param D          (int) the length of the delay line
+   * \param long_form  (bool) whether to use long (true, default) or short form
+   * \param channel (unsigned integer) Selects the channel to return [default=0].
+   */
+  friend gr_dc_blocker_ff_sptr gr_make_dc_blocker_ff (int D, bool long_form);
+
+  int d_length;
+  bool d_long_form;
+  moving_averager_f *d_ma_0;
+  moving_averager_f *d_ma_1;
+  moving_averager_f *d_ma_2;
+  moving_averager_f *d_ma_3;
+  std::deque<float> d_delay_line;
+
+  gr_dc_blocker_ff (int D, bool long_form);
+
+public:
+  ~gr_dc_blocker_ff ();
+
+  /*!
+   * Get the blocker's group delay that is based on length of delay lines
+   */
+  int get_group_delay();
+
+  //int set_length(int D);
+  
+  int work (int noutput_items,
+	    gr_vector_const_void_star &input_items,
+	    gr_vector_void_star &output_items);
+};
+
+#endif
diff --git a/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.i b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.i
new file mode 100644
index 000000000..032145c9e
--- /dev/null
+++ b/gnuradio-core/src/lib/filter/gr_dc_blocker_ff.i
@@ -0,0 +1,34 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2011 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,dc_blocker_ff);
+
+gr_dc_blocker_ff_sptr gr_make_dc_blocker_ff (int D=32, bool long_form=true);
+
+class gr_dc_blocker_ff : public gr_sync_block
+{
+ private:
+  gr_dc_blocker_ff (int D, bool long_form);
+
+ public:
+  ~gr_dc_blocker_ff ();
+};
diff --git a/gnuradio-core/src/python/gnuradio/gr/Makefile.am b/gnuradio-core/src/python/gnuradio/gr/Makefile.am
index f1b4ba2b1..45c970227 100644
--- a/gnuradio-core/src/python/gnuradio/gr/Makefile.am
+++ b/gnuradio-core/src/python/gnuradio/gr/Makefile.am
@@ -55,6 +55,7 @@ noinst_PYTHON = 			\
 	qa_copy.py			\
 	qa_correlate_access_code.py	\
 	qa_delay.py			\
+	qa_dc_blocker.py		\
 	qa_diff_encoder.py		\
 	qa_diff_phasor_cc.py		\
 	qa_ecc_ccsds_27.py		\
diff --git a/gnuradio-core/src/python/gnuradio/gr/qa_dc_blocker.py b/gnuradio-core/src/python/gnuradio/gr/qa_dc_blocker.py
new file mode 100755
index 000000000..8977b475a
--- /dev/null
+++ b/gnuradio-core/src/python/gnuradio/gr/qa_dc_blocker.py
@@ -0,0 +1,108 @@
+#!/usr/bin/env python
+#
+# Copyright 2011 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.
+# 
+
+from gnuradio import gr, gr_unittest
+
+class test_dc_blocker(gr_unittest.TestCase):
+
+    def setUp (self):
+        self.tb = gr.top_block ()
+
+    def tearDown (self):
+        self.tb = None
+
+    def test_001(self):
+        ''' Test impulse response - long form, cc '''
+        src_data = [1,] + 100*[0,] 
+        expected_result = ((-0.02072429656982422+0j), (-0.02081298828125+0j),
+                           (0.979156494140625+0j), (-0.02081298828125+0j),
+                           (-0.02072429656982422+0j))
+
+        src = gr.vector_source_c(src_data)
+        op = gr.dc_blocker_cc(32, True)
+        dst = gr.vector_sink_c()
+
+        self.tb.connect (src, op, dst)
+        self.tb.run()
+
+        # only test samples around 2D-2
+        result_data = dst.data()[60:65]
+        self.assertFloatTuplesAlmostEqual (expected_result, result_data)
+
+    def test_002(self):
+        ''' Test impulse response - short form, cc '''
+        src_data = [1,] + 100*[0,] 
+        expected_result = ((-0.029296875+0j), (-0.0302734375+0j),
+                           (0.96875+0j), (-0.0302734375+0j),
+                           (-0.029296875+0j))
+
+        src = gr.vector_source_c(src_data)
+        op = gr.dc_blocker_cc(32, False)
+        dst = gr.vector_sink_c()
+
+        self.tb.connect (src, op, dst)
+        self.tb.run()
+
+        # only test samples around D-1
+        result_data = dst.data()[29:34]
+        self.assertFloatTuplesAlmostEqual (expected_result, result_data)
+
+
+    def test_003(self):
+        ''' Test impulse response - long form, ff '''
+        src_data = [1,] + 100*[0,] 
+        expected_result = ((-0.02072429656982422), (-0.02081298828125),
+                           (0.979156494140625), (-0.02081298828125),
+                           (-0.02072429656982422))
+
+        src = gr.vector_source_f(src_data)
+        op = gr.dc_blocker_ff(32, True)
+        dst = gr.vector_sink_f()
+
+        self.tb.connect (src, op, dst)
+        self.tb.run()
+
+        # only test samples around 2D-2
+        result_data = dst.data()[60:65]
+        self.assertFloatTuplesAlmostEqual (expected_result, result_data)
+
+    def test_004(self):
+        ''' Test impulse response - short form, ff '''
+        src_data = [1,] + 100*[0,] 
+        expected_result = ((-0.029296875), (-0.0302734375),
+                           (0.96875), (-0.0302734375),
+                           (-0.029296875))
+
+        src = gr.vector_source_f(src_data)
+        op = gr.dc_blocker_ff(32, False)
+        dst = gr.vector_sink_f()
+
+        self.tb.connect (src, op, dst)
+        self.tb.run()
+
+        # only test samples around D-1
+        result_data = dst.data()[29:34]
+        self.assertFloatTuplesAlmostEqual (expected_result, result_data)
+
+if __name__ == '__main__':
+    gr_unittest.run(test_dc_blocker, "test_dc_blocker.xml")
+        
diff --git a/grc/blocks/Makefile.am b/grc/blocks/Makefile.am
index 81eb81182..14ffe8358 100644
--- a/grc/blocks/Makefile.am
+++ b/grc/blocks/Makefile.am
@@ -90,6 +90,7 @@ dist_ourdata_DATA = \
 	gr_correlate_access_code_bb.xml \
 	gr_costas_loop_cc.xml \
 	gr_cpfsk_bc.xml \
+	gr_dc_blocker.xml \
 	gr_decode_ccsds_27_fb.xml \
 	gr_deinterleave.xml \
 	gr_delay.xml \
diff --git a/grc/blocks/block_tree.xml b/grc/blocks/block_tree.xml
index 66094a80d..0b641d79c 100644
--- a/grc/blocks/block_tree.xml
+++ b/grc/blocks/block_tree.xml
@@ -188,6 +188,7 @@
 		<block>gr_keep_one_in_n</block>
 		<block>gr_moving_average_xx</block>
 		<block>gr_iqcomp_cc</block>
+		<block>gr_dc_blocker</block>
 	</cat>
 	<cat>
 		<name>Modulators</name>
diff --git a/grc/blocks/gr_dc_blocker.xml b/grc/blocks/gr_dc_blocker.xml
new file mode 100644
index 000000000..e5aeeb031
--- /dev/null
+++ b/grc/blocks/gr_dc_blocker.xml
@@ -0,0 +1,51 @@
+<?xml version="1.0"?>
+<!--
+###################################################
+## DC Blocker
+###################################################
+ -->
+<block>
+	<name>DC Blocker</name>
+	<key>gr_dc_blocker</key>
+	<import>from gnuradio import gr</import>
+	<make>gr.dc_blocker_$(type)($length, $long_form)</make>
+	<!-- <callback>set_length($lenght)</callback> -->
+	<param>
+		<name>Type</name>
+		<key>type</key>
+		<type>enum</type>
+		<option>
+			<name>Complex->Complex</name>
+			<key>cc</key>
+			<opt>input:complex</opt>
+			<opt>output:complex</opt>
+		</option>
+		<option>
+			<name>Float->Float</name>
+			<key>ff</key>
+			<opt>input:float</opt>
+			<opt>output:float</opt>
+		</option>
+	</param>
+	<param>
+		<name>Length</name>
+		<key>length</key>
+		<value>32</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Long Form</name>
+		<key>long_form</key>
+		<value>True</value>
+		<type>bool</type>
+	</param>
+
+	<sink>
+		<name>in</name>
+		<type>$type.input</type>
+	</sink>
+	<source>
+		<name>out</name>
+		<type>$type.output</type>
+	</source>
+</block>