1 files changed, 82 insertions, 0 deletions
diff --git a/gr-noaa/lib/noaa_hrpt_pll_cf.cc b/gr-noaa/lib/noaa_hrpt_pll_cf.cc
new file mode 100644
index 000000000..08ab1d15f
--- /dev/null
+++ b/gr-noaa/lib/noaa_hrpt_pll_cf.cc
@@ -0,0 +1,82 @@
+/* -*- c++ -*- */
+/*
+ * Copyright 2009 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 <noaa_hrpt_pll_cf.h>
+#include <gr_io_signature.h>
+#include <gr_math.h>
+#include <gr_sincos.h>
+
+#define M_TWOPI (2*M_PI)
+
+noaa_hrpt_pll_cf_sptr
+noaa_make_hrpt_pll_cf(float alpha, float beta, float max_offset)
+{
+  return gnuradio::get_initial_sptr(new noaa_hrpt_pll_cf(alpha, beta, max_offset));
+}
+
+noaa_hrpt_pll_cf::noaa_hrpt_pll_cf(float alpha, float beta, float max_offset)
+  : gr_sync_block("noaa_hrpt_pll_cf",
+		  gr_make_io_signature(1, 1, sizeof(gr_complex)),
+		  gr_make_io_signature(1, 1, sizeof(float))),
+    d_alpha(alpha), d_beta(beta), d_max_offset(max_offset),
+    d_phase(0.0), d_freq(0.0)
+{
+}
+
+float
+phase_wrap(float phase)
+{
+  while (phase < -M_PI)
+    phase += M_TWOPI;
+  while (phase > M_PI)
+    phase -= M_TWOPI;
+
+  return phase;
+}
+
+int
+noaa_hrpt_pll_cf::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];
+  float *out = (float *) output_items[0];
+
+  for (int i = 0; i < noutput_items; i++) {
+
+    // Adjust PLL phase/frequency
+    float error = phase_wrap(gr_fast_atan2f(in[i].imag(), in[i].real()) - d_phase);
+    d_freq  = gr_branchless_clip(d_freq + error*d_beta, d_max_offset);
+    d_phase = phase_wrap(d_phase + error*d_alpha + d_freq);
+
+    // Generate and mix out carrier
+    float re, im;
+    gr_sincosf(d_phase, &im, &re);
+    out[i] = (in[i]*gr_complex(re, -im)).imag();
+  }
+
+  return noutput_items;
+}