1 files changed, 106 insertions, 0 deletions
diff --git a/gr-atsc/lib/GrAtscConvert2xTo20.cc b/gr-atsc/lib/GrAtscConvert2xTo20.cc
new file mode 100644
index 0000000000..ac22ee1258
--- /dev/null
+++ b/gr-atsc/lib/GrAtscConvert2xTo20.cc
@@ -0,0 +1,106 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2002 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 <atsc/GrAtscConvert2xTo20.h>
+#include <atsc/consts.h>
+#include <cmath>
+#include <cstdio>
+
+static const int    N_OUTPUTS = 1;
+static const double DEC_RATIO = (2.0 * ATSC_SYMBOL_RATE) / 20e6;	// ~ 1.076
+
+GrAtscConvert2xTo20::GrAtscConvert2xTo20 ()
+  : VrDecimatingSigProc<float,float> (N_OUTPUTS, (int) rint (DEC_RATIO))
+{
+  d_next_input = 0;
+  d_frac_part = 0;
+  history = 2 * d_interp.ntaps ();	// some slack
+}
+
+GrAtscConvert2xTo20::~GrAtscConvert2xTo20 ()
+{
+  // Nop
+}
+
+void
+GrAtscConvert2xTo20::pre_initialize ()
+{
+  fprintf (stderr,
+	   "GrAtscConvert2xTo20: input freq = %g\n", getInputSamplingFrequencyN(0));
+  fprintf (stderr,
+	   "GrAtscConvert2xTo20: DEC_RATIO = %g\n", DEC_RATIO);
+  fprintf (stderr,
+	   "GrAtscConvert2xTo20: argument to setSamplingFrequency = %g\n",
+	   getInputSamplingFrequencyN(0) / DEC_RATIO);
+
+  int	r;
+  r = setSamplingFrequency (getInputSamplingFrequencyN (0) / DEC_RATIO);
+
+  fprintf (stderr, "GrAtscConvert2xTo20: result = %d\n", r);
+
+  fprintf (stderr, "GrAtscConvert2xTo20: getSamplingFrequency = %g\n",
+	   getSamplingFrequency ());
+}
+
+
+int
+GrAtscConvert2xTo20::forecast (VrSampleRange output,
+			       VrSampleRange inputs[])
+{
+  assert (numberInputs == 1);	// I hate these free references to
+				// superclass's instance variables...
+
+  inputs[0].index = d_next_input;
+  inputs[0].size =
+    ((long unsigned int) (output.size * DEC_RATIO) + history - 1);
+
+  return 0;
+}
+
+int
+GrAtscConvert2xTo20::work (VrSampleRange output, void *ao[],
+			   VrSampleRange inputs[], void *ai[])
+{
+  float	*in = ((float **) ai)[0];
+  float *out = ((float **) ao)[0];
+
+  sync (output.index);
+
+  unsigned long  si = 0;		// source index
+  unsigned long	 oi = 0;		// output index
+  double frac_part = d_frac_part;
+
+  for (oi = 0; oi < output.size; oi++){
+    assert (si + d_interp.ntaps () < inputs[0].size);
+    out[oi] = d_interp.interpolate (&in[si], (1. - frac_part));
+
+    double s = frac_part + DEC_RATIO;
+    double float_incr = floor (s);
+    frac_part = s - float_incr;
+    int incr = (int) float_incr;
+    si += incr;
+  }
+
+  d_next_input += si;
+  d_frac_part = frac_part;
+  return output.size;
+}