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Test for Decode CCSDS 27 degradation bug
#!/usr/bin/env python2
import math
import numpy
from gnuradio import gr, digital
from gnuradio import blocks
from gnuradio import fec
# Best to choose powers of 10
N_BITS = 1e8
SKIP = 1000
class BitErrors(gr.hier_block2):
def __init__(self):
gr.hier_block2.__init__(self, "BitErrors",
gr.io_signature(1, 1, gr.sizeof_char),
gr.io_signature(1, 1, gr.sizeof_int))
# Bit comparison
intdump_decim = 100000
self.connect(self,
# skip first samples
blocks.skiphead(gr.sizeof_char, SKIP),
# exchange 0 <-> 1
blocks.not_bb(),
blocks.and_const_bb(1),
# average over blocks of intdump_decim samples
blocks.uchar_to_float(),
blocks.integrate_ff(intdump_decim),
blocks.multiply_const_ff(1.0/intdump_decim),
self)
class BERAWGNSimu(gr.top_block):
" This contains the simulation flow graph "
def __init__(self, use_decode_ccsds_27):
gr.top_block.__init__(self)
self.sink = blocks.vector_sink_f()
descrambler = digital.descrambler_bb(0x21, 0x00, 16)
add_const = blocks.add_const_ff(-0.5)
# generate stream of 1's, G3RUH scramble and CC-encode
self.connect(blocks.vector_source_b([1]*int(N_BITS), False),
digital.scrambler_bb(0x21, 0x00, 16),
blocks.pack_k_bits_bb(8),
fec.encode_ccsds_27_bb(),
blocks.uchar_to_float(),
add_const)
if use_decode_ccsds_27:
# CC-decode with decode_ccsds_27_fb
self.connect(add_const,
fec.decode_ccsds_27_fb(),
blocks.unpack_k_bits_bb(8),
descrambler)
else:
# CC-decode with fec.cc_decoder
self.connect(add_const,
fec.extended_decoder(fec.cc_decoder.make(800, 7, 2, [109, 79]), None),
descrambler)
# G3RUH descrambler and count bit errors
self.connect(descrambler,
digital.descrambler_bb(0x21, 0x00, 16),
BitErrors(),
self.sink)
if __name__ == "__main__":
print 'BER with decode_ccsds_27_fb'
fg = BERAWGNSimu(True)
fg.run()
print fg.sink.data()
print 'BER with fec.cc_decoder'
fg = BERAWGNSimu(False)
fg.run()
print fg.sink.data()
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