From cd963d806b7f324fd845c7b51ef20985000b774c Mon Sep 17 00:00:00 2001
From: Tom Rondeau <trondeau@vt.edu>
Date: Mon, 12 Oct 2009 13:26:00 -0400
Subject: Working DBPSK implementation with new PFB clock recovery block. The
feedforward AGC wasn't playing nicely, the frequency aquistion range was
increased to swing half the sample rate in either direction, and the number
of filter phases to use was increased to 32.
---
gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
(limited to 'gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py')
diff --git a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
index e9e3e965fe..e2bce5ff08 100644
--- a/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
+++ b/gnuradio-core/src/python/gnuradio/blks2impl/dbpsk2.py
@@ -230,12 +230,13 @@ class dbpsk2_demod(gr.hier_block2):
arity = pow(2,self.bits_per_symbol())
# Automatic gain control
- #self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
- self.agc = gr.feedforward_agc_cc(16, 1.0)
+ self.agc = gr.agc2_cc(0.6e-1, 1e-3, 1, 1, 100)
+ #self.agc = gr.feedforward_agc_cc(16, 1.0)
self._costas_beta = 0.25 * self._costas_alpha * self._costas_alpha
- fmin = -0.25
- fmax = 0.25
+ # Allow a frequency swing of +/- half of the sample rate
+ fmin = -0.5
+ fmax = 0.5
self.clock_recov = gr.costas_loop_cc(self._costas_alpha,
self._costas_beta,
@@ -247,9 +248,9 @@ class dbpsk2_demod(gr.hier_block2):
self._timing_beta = 0.020
# RRC data filter
- nfilts = 8
+ nfilts = 32
ntaps = 11 * samples_per_symbol*nfilts
- taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 0.25, self._excess_bw, ntaps)
+ taps = gr.firdes.root_raised_cosine(nfilts, nfilts, 1.0/float(self._samples_per_symbol), self._excess_bw, ntaps)
self.time_recov = gr.pfb_clock_sync_ccf(self._samples_per_symbol,
self._timing_alpha,
taps, nfilts, nfilts/2, self._timing_max_dev)
@@ -279,7 +280,7 @@ class dbpsk2_demod(gr.hier_block2):
# Connect and Initialize base class
self.connect(self, self.agc,
- #self.clock_recov,
+ self.clock_recov,
self.time_recov,
self.diffdec, self.slicer, self.symbol_mapper, self.unpack, self)
--
cgit v1.2.3