From 9b2c992cf1055afb35780e1eba799243d8be2dae Mon Sep 17 00:00:00 2001
From: Piotr Krysik <perper@o2.pl>
Date: Mon, 22 Jun 2009 17:22:07 +0200
Subject: added first step towards correction of USRP's clock offset

---
 src/lib/gsm.i              |  4 ++--
 src/lib/gsm_receiver_cf.cc |  6 +++---
 src/lib/gsm_receiver_cf.h  |  9 ++++-----
 src/python/gsm_receive.py  | 29 +++++++++++++++++++----------
 4 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/lib/gsm.i b/src/lib/gsm.i
index 8c4d79a..b5a33f2 100644
--- a/src/lib/gsm.i
+++ b/src/lib/gsm.i
@@ -38,12 +38,12 @@
 
 GR_SWIG_BLOCK_MAGIC(gsm,receiver_cf);
 
-gsm_receiver_cf_sptr gsm_make_receiver_cf ( gr_feval_dd *tuner, int osr);
+gsm_receiver_cf_sptr gsm_make_receiver_cf ( gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr);
 
 class gsm_receiver_cf : public gr_block
 {
 private:
-  gsm_receiver_cf ( gr_feval_dd *tuner, int osr);
+  gsm_receiver_cf ( gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr);
 };
 
 // ----------------------------------------------------------------
diff --git a/src/lib/gsm_receiver_cf.cc b/src/lib/gsm_receiver_cf.cc
index c9ef010..e314381 100644
--- a/src/lib/gsm_receiver_cf.cc
+++ b/src/lib/gsm_receiver_cf.cc
@@ -72,9 +72,9 @@ typedef std::vector<float> vector_float;
 typedef boost::circular_buffer<float> circular_buffer_float;
 
 gsm_receiver_cf_sptr
-gsm_make_receiver_cf(gr_feval_dd *tuner, int osr)
+gsm_make_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr)
 {
-  return gsm_receiver_cf_sptr(new gsm_receiver_cf(tuner, osr));
+  return gsm_receiver_cf_sptr(new gsm_receiver_cf(tuner, synchronizer, osr));
 }
 
 static const int MIN_IN = 1; // mininum number of input streams
@@ -85,7 +85,7 @@ static const int MAX_OUT = 1; // maximum number of output streams
 /*
  * The private constructor
  */
-gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, int osr)
+gsm_receiver_cf::gsm_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr)
     : gr_block("gsm_receiver",
                gr_make_io_signature(MIN_IN, MAX_IN, sizeof(gr_complex)),
                gr_make_io_signature(MIN_OUT, MAX_OUT, 142 * sizeof(float))),
diff --git a/src/lib/gsm_receiver_cf.h b/src/lib/gsm_receiver_cf.h
index 070f9cf..9454997 100644
--- a/src/lib/gsm_receiver_cf.h
+++ b/src/lib/gsm_receiver_cf.h
@@ -37,7 +37,7 @@ class gsm_receiver_cf;
 typedef boost::shared_ptr<gsm_receiver_cf> gsm_receiver_cf_sptr;
 typedef std::vector<gr_complex> vector_complex;
 
-gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, int osr);
+gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr);
 
 /** GSM Receiver GNU Radio block
  *
@@ -61,6 +61,7 @@ class gsm_receiver_cf : public gr_block
     gr_complex d_norm_training_seq[TRAIN_SEQ_NUM][N_TRAIN_BITS]; ///<encoded training sequences of a normal bursts and dummy bursts
 
     gr_feval_dd *d_tuner; ///<callback to a python object which is used for frequency tunning
+    gr_feval_dd *d_synchronizer; ///<callback to a python object which is used to correct offset of USRP's internal clock
 
     /** Countes samples consumed by the receiver
      *
@@ -103,8 +104,8 @@ class gsm_receiver_cf : public gr_block
     // GSM Stack
     GS_CTX d_gs_ctx;//TODO: remove it! it'a not right place for a decoder
 
-    friend gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, int osr);
-    gsm_receiver_cf(gr_feval_dd *tuner, int osr);
+    friend gsm_receiver_cf_sptr gsm_make_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr);
+    gsm_receiver_cf(gr_feval_dd *tuner, gr_feval_dd *synchronizer, int osr);
 
     /** Function whis is used to search a FCCH burst and to compute frequency offset before
      * "synchronized" state of the receiver
@@ -212,8 +213,6 @@ class gsm_receiver_cf : public gr_block
 
     /**
      *
-     * @param burst_nr
-     * @param burst_binary
      */
     void process_normal_burst(burst_counter burst_nr, const unsigned char * burst_binary);
 
diff --git a/src/python/gsm_receive.py b/src/python/gsm_receive.py
index c7aad62..40c1520 100755
--- a/src/python/gsm_receive.py
+++ b/src/python/gsm_receive.py
@@ -9,23 +9,31 @@ from os import sys
 for extdir in ['../../debug/src/lib','../../debug/src/lib/.libs']:
     if extdir not in sys.path:
         sys.path.append(extdir)
-import gsm                        
+import gsm
 
-class tune(gr.feval_dd):
+class tuner(gr.feval_dd):
     def __init__(self, top_block):
         gr.feval_dd.__init__(self)
         self.top_block = top_block
-        # self.center_freq = 0
     def eval(self, freq_offet):
-        # self.center_freq = self.center_freq - freq_offet
-        self.top_block.set_frequency(freq_offet)
+        self.top_block.set_center_frequency(freq_offet)
+        return freq_offet
+
+class synchronizer(gr.feval_dd):
+    def __init__(self, top_block):
+        gr.feval_dd.__init__(self)
+        self.top_block = top_block
+
+    def eval(self, timing_offset):
+        self.top_block.set_timing(timing_offset)
         return freq_offet
 
 class gsm_receiver_first_blood(gr.top_block):
     def __init__(self):
         gr.top_block.__init__(self)
         (options, args) = self._process_options()
-        self.tune_callback = tune(self)
+        self.tuner_callback = tuner(self)
+        self.synchronizer_callback = synchronizer(self)
         self.options    = options
         self.args       = args
         self._set_rates()
@@ -74,7 +82,7 @@ class gsm_receiver_first_blood(gr.top_block):
         return interpolator
     
     def _set_receiver(self):
-        receiver = gsm.receiver_cf(self.tune_callback, self.options.osr)
+        receiver = gsm.receiver_cf(self.tuner_callback, self.synchronizer_callback, self.options.osr)
         return receiver
     
     def _process_options(self):
@@ -90,9 +98,12 @@ class gsm_receiver_first_blood(gr.top_block):
         (options, args) = parser.parse_args ()
         return (options, args)
     
-    def set_frequency(self, center_freq):
+    def set_center_frequency(self, center_freq):
         self.filtr.set_center_freq(center_freq)
 
+    def set_timing(self, timing_offset):
+        pass
+
 def main():
     try:
         gsm_receiver_first_blood().run()
@@ -101,5 +112,3 @@ def main():
 
 if __name__ == '__main__':
     main()
-
-
-- 
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