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#!/usr/bin/env python3
# -*- coding: utf-8 -*-
# Copyright 2019 Daniel Estevez <daniel@destevez.net>
#
# This file is part of gr-satellites
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
from gnuradio import gr, digital, blocks, fec
from ... import descrambler308
from ... import k2sat_deframer as deframer
from ...hier.sync_to_pdu_packed import sync_to_pdu_packed
from ...utils.options_block import options_block
_syncword = '0101010101111110'
class k2sat_deframer(gr.hier_block2, options_block):
"""
Hierarchical block to deframe the K2SAT custom image protocol
The input is a float stream of soft symbols. The output are PDUs
with frames.
Args:
syncword_threshold: number of bit errors allowed in syncword (int)
options: Options from argparse
"""
def __init__(self, syncword_threshold=None, options=None):
gr.hier_block2.__init__(
self,
'k2sat_deframer',
gr.io_signature(1, 1, gr.sizeof_float),
gr.io_signature(0, 0, 0))
options_block.__init__(self, options)
self.message_port_register_hier_out('out')
if syncword_threshold is None:
syncword_threshold = self.options.syncword_threshold
# For QPKS 90ยบ abiguity
self.deinterleave = blocks.deinterleave(gr.sizeof_float, 1)
self.invert = blocks.multiply_const_ff(-1, 1)
self.interleave = blocks.interleave(gr.sizeof_float, 1)
self.cc0 = fec.cc_decoder.make(
80, 7, 2, [79, 109], 0, -1, fec.CC_STREAMING, False)
self.cc1 = fec.cc_decoder.make(
80, 7, 2, [79, 109], 0, -1, fec.CC_STREAMING, False)
self.viterbi0 = fec.extended_decoder(
decoder_obj_list=self.cc0, threading=None, ann=None,
puncpat='11')
self.viterbi1 = fec.extended_decoder(
decoder_obj_list=self.cc1, threading=None, ann=None,
puncpat='11')
self.diff0 = digital.diff_decoder_bb(2)
self.diff1 = digital.diff_decoder_bb(2)
self.scrambler0 = descrambler308()
self.scrambler1 = descrambler308()
self.deframer0 = sync_to_pdu_packed(
packlen=2200, sync=_syncword, threshold=syncword_threshold)
self.deframer1 = sync_to_pdu_packed(
packlen=2200, sync=_syncword, threshold=syncword_threshold)
self.deframer = deframer()
self.connect(self, self.viterbi0, self.diff0,
self.scrambler0, self.deframer0)
self.connect(self, self.deinterleave)
self.connect((self.deinterleave, 0), (self.interleave, 1))
self.connect((self.deinterleave, 1), self.invert, (self.interleave, 0))
self.connect(self.interleave, self.viterbi1, self.diff1,
self.scrambler1, self.deframer1)
self.msg_connect((self.deframer0, 'out'), (self.deframer, 'in'))
self.msg_connect((self.deframer1, 'out'), (self.deframer, 'in'))
self.msg_connect((self.deframer, 'out'), (self, 'out'))
_default_sync_threshold = 0
@classmethod
def add_options(cls, parser):
"""
Adds K2SAT deframer specific options to the argparse parser
"""
parser.add_argument(
'--syncword_threshold', type=int,
default=cls._default_sync_threshold,
help='Syncword bit errors [default=%(default)r]')
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