Merge branch 'upstream' into dfsg-orig

[debian/gnuradio] / gr-atsc / src / lib / atsci_vsbtx_lp.cc

diff --git a/gr-atsc/src/lib/atsci_vsbtx_lp.cc b/gr-atsc/src/lib/atsci_vsbtx_lp.cc
new file mode 100644 (file)
index 0000000..224d29a
--- /dev/null
+++ b/gr-atsc/src/lib/atsci_vsbtx_lp.cc
@@ -0,0 +1,59 @@
+/* -*- 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_consts.h>
+#include <atsci_vsbtx_lp.h>
+#include <stdexcept>
+#include <cmath>
+#include <iostream>
+
+using std::vector;
+using std::cerr;
+using std::endl;
+
+// atsc root raised cosine filter, sampling rate = 21.52 MHz
+static const float atsc_vsbtx_lp2x[] = {
+#include "atsc_vsbtx_lp.dat"
+};
+
+#define NELEM(x) (sizeof (x) / sizeof ((x)[0]))
+
+// is a within 5% of target?
+
+static bool 
+close_enough_p (double a, double target)
+{
+  double delta = fabs (target * 0.05); //  5 percent
+
+  return fabs (target - a) <= delta;
+}
+
+vector<float> 
+atsc_vsbtx_lp::taps (double sampling_freq)
+{
+  if (close_enough_p (sampling_freq, 2 * ATSC_SYMBOL_RATE)){
+    return vector<float>(&atsc_vsbtx_lp2x[0], &atsc_vsbtx_lp2x[NELEM(atsc_vsbtx_lp2x)]);
+  }
+  else
+    throw std::out_of_range (
+     "atsc_vsbtx_lp: no pre-designed filter close enough");
+}