Added new blocks for clock freqeuncy correction
diff --git a/python/clock_offset_control.py b/python/clock_offset_control.py
new file mode 100644
index 0000000..133368c
--- /dev/null
+++ b/python/clock_offset_control.py
@@ -0,0 +1,76 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# Copyright 2014 <+YOU OR YOUR COMPANY+>.
+#
+# This 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.
+#
+# This software 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 this software; see the file COPYING. If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+from numpy import *
+from gnuradio import gr
+import pmt
+
+class clock_offset_control(gr.basic_block):
+ """
+ docstring for block clock_offset_control
+ """
+ def __init__(self, fc, samp_rate):
+ gr.basic_block.__init__(self,
+ name="clock_offset_control",
+ in_sig=[],
+ out_sig=[])
+ self.fc = fc
+ self.samp_rate = samp_rate
+ self.message_port_register_in(pmt.intern("measurements"))
+ self.set_msg_handler(pmt.intern("measurements"), self.process_measurement)
+ self.message_port_register_out(pmt.intern("ppm"))
+ self.alfa = 0.6
+ self.ppm_estimate = -1e6
+ self.first_measurement = True
+ self.counter = 0
+
+ def process_measurement(self,msg):
+ if pmt.is_tuple(msg):
+ key = pmt.symbol_to_string(pmt.tuple_ref(msg,0))
+ if key == "freq_offset":
+ freq_offset = pmt.to_double(pmt.tuple_ref(msg,1))
+ ppm = -freq_offset/self.fc*1.0e6
+ state = pmt.symbol_to_string(pmt.tuple_ref(msg,2))
+
+ if state == "first_fcch_search" or state == "next_fcch_search":
+ msg_ppm = pmt.from_double(ppm)
+ self.message_port_pub(pmt.intern("ppm"), msg_ppm)
+
+ if state == "synchronized":
+ if self.first_measurement:
+ self.ppm_estimate = ppm
+ self.first_measurement = False
+ else:
+ self.ppm_estimate = (1-self.alfa)*self.ppm_estimate+self.alfa*ppm
+
+ if self.counter == 5:
+ self.counter = 0
+ msg_ppm = pmt.from_double(ppm)
+ self.message_port_pub(pmt.intern("ppm"), msg_ppm)
+ else:
+ self.counter=self.counter+1
+
+ if state == "sync_loss":
+ self.ppm_estimate = -1e6
+ self.counter = 0
+ self.first_measurement = True
+ msg_ppm = pmt.from_double(0.0)
+ self.message_port_pub(pmt.intern("ppm"), msg_ppm)