[Commit-gnuradio] r3934 - gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl

[trondeau]

Author: trondeau
Date: 2006-11-04 14:25:35 -0700 (Sat, 04 Nov 2006)
New Revision: 3934

Modified:
   
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py
Log:
removed Costas loop from BPSK demodulator -- carier sync is taken care of by 
the rest of the system

Modified: 
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py
===================================================================
--- 
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py
       2006-11-04 21:24:18 UTC (rev 3933)
+++ 
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dbpsk.py
       2006-11-04 21:25:35 UTC (rev 3934)
@@ -241,10 +241,12 @@
 
         
         # Costas loop (carrier tracking)
-        # FIXME: need to decide how to handle this more generally; do we pull 
it from higher layer?
-        costas_order = 2
-        beta = .25 * self._costas_alpha * self._costas_alpha
-        self.costas_loop = gr.costas_loop_cc(self._costas_alpha, beta, 0.002, 
-0.002, costas_order)
+        # The Costas loop is not needed for BPSK (thanks to other nice 
properties of the system, the M&M
+        # block in particular. Uncomment these lines to add it back in and 
readd to the flow graph
+        # if your purposes demand its use.
+        #costas_order = 2
+        #beta = .25 * self._costas_alpha * self._costas_alpha
+        #self.costas_loop = gr.costas_loop_cc(self._costas_alpha, beta, 0.002, 
-0.002, costas_order)
 
         # RRC data filter
         ntaps = 11 * self._samples_per_symbol
@@ -289,7 +291,7 @@
             self._setup_logging()
 
         # Connect and Initialize base class
-        self._fg.connect(self.pre_scaler, self.agc, self.costas_loop,
+        self._fg.connect(self.pre_scaler, self.agc, #self.costas_loop,
                          self.rrc_filter, self.clock_recovery, self.diffdec,
                          self.slicer, self.symbol_mapper, self.unpack)
 
@@ -306,7 +308,7 @@
         print "bits per symbol = %d"         % self.bits_per_symbol()
         print "Gray code = %s"               % self._gray_code
         print "RRC roll-off factor = %.2f"   % self._excess_bw
-        print "Costas Loop alpha = %.5f"     % self._costas_alpha
+        #print "Costas Loop alpha = %.5f"     % self._costas_alpha
         print "M&M symbol sync gain = %.5f"  % self._gain_mu
         print "M&M symbol sync mu = %.5f"    % self._mu
         print "M&M omega relative limit = %.5f" % self._omega_relative_limit
@@ -317,10 +319,10 @@
                          gr.file_sink(gr.sizeof_gr_complex, "prescaler.dat"))
         self._fg.connect(self.agc,
                          gr.file_sink(gr.sizeof_gr_complex, "agc.dat"))
-        self._fg.connect(self.costas_loop,
-                         gr.file_sink(gr.sizeof_gr_complex, "costas_loop.dat"))
-        self._fg.connect((self.costas_loop,1),
-                         gr.file_sink(gr.sizeof_gr_complex, 
"costas_error.dat"))
+        #self._fg.connect(self.costas_loop,
+        #                 gr.file_sink(gr.sizeof_gr_complex, 
"costas_loop.dat"))
+        #self._fg.connect((self.costas_loop,1),
+        #                 gr.file_sink(gr.sizeof_gr_complex, 
"costas_error.dat"))
         self._fg.connect(self.rrc_filter,
                          gr.file_sink(gr.sizeof_gr_complex, "rrc_filter.dat"))
         self._fg.connect(self.clock_recovery,