1 files changed, 62 insertions, 0 deletions
diff --git a/gnuradio-examples/python/digital-bert/transmit_path.py b/gnuradio-examples/python/digital-bert/transmit_path.py
new file mode 100644
index 000000000..47b6ab229
--- /dev/null
+++ b/gnuradio-examples/python/digital-bert/transmit_path.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+#
+# Copyright 2008 Free Software Foundation, Inc.
+#
+# This file is part of GNU Radio
+#
+# GNU Radio 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.
+#
+# GNU Radio 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 GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+#
+
+from gnuradio import gr
+from math import pi, log10
+import cmath
+
+class transmit_path(gr.hier_block2):
+    """
+    This transmits a BERT sequence of bits using filtered BPSK and
+    outputs the complex baseband waveform.
+    """
+    def __init__(self,
+                 sps,          # Samples per symbol
+                 excess_bw,    # RRC filter excess bandwidth (typically 0.35-0.5)
+                 amplitude     # DAC output level, 0-32767, typically 2000-8000
+                 ):
+
+        gr.hier_block2.__init__(self, "transmit_path",
+                                gr.io_signature(0, 0, 0),                    # Input signature
+                                gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
+
+        # Create BERT data bit stream	
+	self._bits = gr.vector_source_b([1,], True)      # Infinite stream of ones
+        self._scrambler = gr.scrambler_bb(0x8A, 0x7F, 7) # CCSDS 7-bit scrambler
+
+	# Map to constellation
+	self._constellation = [-1+0j, 1+0j]
+	self._mapper = gr.chunks_to_symbols_bc(self._constellation)	
+
+	# Create RRC with specified excess bandwidth
+	taps = gr.firdes.root_raised_cosine(sps*amplitude,  # Gain
+					    sps,	    # Sampling rate
+					    1.0,	    # Symbol rate
+					    excess_bw,	    # Roll-off factor
+					    11*sps)         # Number of taps
+
+	self._rrc = gr.interp_fir_filter_ccf(sps,	    # Interpolation rate
+					     taps)	    # FIR taps
+
+        # Wire block inputs and outputs
+        self.connect(self._bits, self._scrambler, self._mapper, self._rrc, self)
+