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[Commit-gnuradio] r3945 - gnuradio/branches/developers/trondeau/digital-
From: |
trondeau |
Subject: |
[Commit-gnuradio] r3945 - gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl |
Date: |
Sun, 5 Nov 2006 13:56:09 -0700 (MST) |
Author: trondeau
Date: 2006-11-05 13:56:09 -0700 (Sun, 05 Nov 2006)
New Revision: 3945
Modified:
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dqpsk.py
Log:
adjusted Costas gain values for different SPS; user can override these defaults
Modified:
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dqpsk.py
===================================================================
---
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dqpsk.py
2006-11-05 19:42:19 UTC (rev 3944)
+++
gnuradio/branches/developers/trondeau/digital-wip/gnuradio-core/src/python/gnuradio/blksimpl/dqpsk.py
2006-11-05 20:56:09 UTC (rev 3945)
@@ -39,7 +39,7 @@
_def_verbose = False
_def_log = False
-_def_costas_alpha = 0.10
+_def_costas_alpha = 0.0
_def_gain_mu = 0.03
_def_mu = 0.05
_def_omega_relative_limit = 0.005
@@ -238,11 +238,15 @@
self.agc = gr.feedforward_agc_cc(16, 1.0)
# Costas loop (carrier tracking)
- costas_order = 4
+ if self._costas_alpha == 0.0: # If no alpha value was specified by
the user
+ alpha_dir = {2:0.075, 3:0.075, 4:0.105, 5:0.105, 6:0.125, 7:0.130}
+ self._costas_alpha = alpha_dir[self._samples_per_symbol]
+
+ costas_order = 4
# The value of beta is now set to be overdamped; this value can have a
huge impact on the
# performance of QPSK. Set to 0.25 for critically damped or higher for
underdamped responses.
- beta = .10 * self._costas_alpha * self._costas_alpha
- self.costas_loop = gr.costas_loop_cc(self._costas_alpha, beta, 0.002,
-0.002, costas_order)
+ beta = .15 * self._costas_alpha * self._costas_alpha
+ self.costas_loop = gr.costas_loop_cc(self._costas_alpha, beta, 0.02,
-0.02, costas_order)
# RRC data filter
ntaps = 11 * samples_per_symbol
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