1 files changed, 84 insertions, 0 deletions
diff --git a/gr-atsc/lib/atsci_exp2_lp.cc b/gr-atsc/lib/atsci_exp2_lp.cc
new file mode 100644
index 0000000000..93e15f7023
--- /dev/null
+++ b/gr-atsc/lib/atsci_exp2_lp.cc
@@ -0,0 +1,84 @@
+/* -*- 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 <atsc/exp2_lp_impl.h>
+#include <stdexcept>
+#include <cmath>
+#include <iostream>
+
+using std::vector;
+using std::cerr;
+using std::endl;
+
+/*
+ * FILTER SPECIFICATION FILE
+ * FILTER TYPE:LOW PASS                       1H
+ * PASSBAND RIPPLE IN -dB            -.0100
+ * STOPBAND RIPPLE IN -dB          -66.0000
+ * PASSBAND CUTOFF FREQUENCY    5.69000     HERTZ
+ * STOPBAND CUTOFF FREQUENCY    6.12000     HERTZ
+ * SAMPLING FREQUENCY           21.5200     HERTZ
+ */
+static const float atsci_exp2_lp2x[] = {
+#include "atsci_exp2_lp2x.dat"
+};
+
+/*
+ * FILTER SPECIFICATION FILE
+ * FILTER TYPE:LOW PASS                       1H
+ * PASSBAND RIPPLE IN -dB            -.0100
+ * STOPBAND RIPPLE IN -dB          -66.0000
+ * PASSBAND CUTOFF FREQUENCY    5.69000     HERTZ
+ * STOPBAND CUTOFF FREQUENCY    6.12000     HERTZ
+ * SAMPLING FREQUENCY           20.0000     HERTZ
+ */
+static const float atsci_exp2_lp20[] = {
+#include "atsci_exp2_lp20.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>
+atsci_exp2_lp::taps (double sampling_freq)
+{
+  if (close_enough_p (sampling_freq, 20e6)){
+    return vector<float>(&atsci_exp2_lp20[0], &atsci_exp2_lp20[NELEM(atsci_exp2_lp20)]);
+  }
+  if (close_enough_p (sampling_freq, 2 * ATSC_SYMBOL_RATE)){
+    return vector<float>(&atsci_exp2_lp2x[0], &atsci_exp2_lp2x[NELEM(atsci_exp2_lp2x)]);
+  }
+  else
+    throw std::out_of_range (
+     "atsci_exp2_lp: no pre-designed filter close enough");
+}