Ryan Malloy
5867c54de3
Ported from zleffke/gr-sarsat (2018, GNU Radio 3.7): - Updated Python 2 → Python 3 - Converted XML block definitions to YAML - Added pyproject.toml for modern packaging - Preserved original MIT license Blocks: - biphase_l_decode_bb: Manchester decoder (decim_block) - pds_frame_sync: Frame synchronizer with PDU output - sarp_msg_extract: SARP message splitter/validator
46 lines
1.1 KiB
Python
46 lines
1.1 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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# MIT License
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# Copyright (c) 2018 zleffke
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# Ported to GNU Radio 3.10+ by gr-mcp
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"""
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Biphase-L Decoder for Cospas-Sarsat 406 MHz beacons.
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Biphase-L (Manchester) encoding represents:
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- Bit 0: Low-to-High transition at bit center
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- Bit 1: High-to-Low transition at bit center
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This decoder extracts the data bit from each symbol pair.
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"""
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import numpy as np
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from gnuradio import gr
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class biphase_l_decode_bb(gr.decim_block):
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"""
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Biphase-L Decoder.
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Input: Unpacked byte stream of Biphase-L encoded symbols (2 samples per bit).
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Output: Unpacked byte stream of decoded bits.
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Decimation factor: 2 (two input samples produce one output bit)
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"""
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def __init__(self):
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gr.decim_block.__init__(
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self,
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name="biphase_l_decode_bb",
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in_sig=[np.int8],
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out_sig=[np.int8],
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decim=2,
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)
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def work(self, input_items, output_items):
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in0 = input_items[0]
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out = output_items[0]
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# Extract first sample of each symbol pair (the data bit value)
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out[:] = in0[::2]
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return len(output_items[0])
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