mirror of https://github.com/hb9fxq/gr-digitalhf
101 lines
3.2 KiB
Python
101 lines
3.2 KiB
Python
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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#
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# Copyright 2018 hcab14@mail.com.
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#
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# This is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3, or (at your option)
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# any later version.
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#
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# This software is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this software; see the file COPYING. If not, write to
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# the Free Software Foundation, Inc., 51 Franklin Street,
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# Boston, MA 02110-1301, USA.
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#
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import digitalhf.digitalhf_swig as digitalhf
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import pmt
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import numpy as np
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def bit2llr(b):
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return 7.0*(1 - 2*b)
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class ViterbiEncoder(object):
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def __init__(self, k, taps):
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self._state = np.zeros(k, dtype=np.uint16)
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self._taps = taps
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def encode(self, bit):
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self._state = np.roll(self._state, 1)
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self._state[0] = bit
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return [bit2llr(self._state.dot(tap) % 2) for tap in self._taps]
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def run_test(N, data):
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decoder = data['dec'](*data['polys'])
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encoder = ViterbiEncoder(data['k'], data['taps'])
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k = data['k']
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for p,t in zip(data['polys'], data['taps']):
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_t = [b=='1' for b in np.binary_repr(p,k)]
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test = _t == t[::-1]
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if not test:
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raise Exception('inconsistent taps', _t, t[::-1])
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np.random.seed(123)
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bits = np.random.randint(2, size=N)
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M = len(data['polys'])
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llr_encoded_bits = np.zeros(M*N, dtype=np.float64)
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for i in range(N-k+1,N):
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encoder.encode(bits[i])
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for i in range(0,N):
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llr_encoded_bits[M*i:M*(i+1)] = encoder.encode(bits[i])
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print(llr_encoded_bits[:14])
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llr_encoded_bits[3::4] = 0
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decoded_bits = np.roll(decoder.udpate(llr_encoded_bits), 0)
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print(decoded_bits.tolist())
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print(bits.tolist())
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print('quality:', decoder.quality(), 100*4/3.5*decoder.quality()/M/N)
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test = [np.all(decoded_bits == bits), abs(4/3.5*decoder.quality()-M*N)<1]
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print('test:', test)
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if not all(test):
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raise Exception(test)
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def main():
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data = [{'dec' : digitalhf.viterbi27,
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'polys': [0x6D, 0x4F],
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'k' : 7,
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'taps' : [[1,0,1,1,0,1,1],
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[1,1,1,1,0,0,1]]},
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{'dec' : digitalhf.viterbi29,
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'polys': [0x11d, 0x1af],
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'k' : 9,
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'taps' : [[1,0,1,1,1,0,0,0,1],
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[1,1,1,1,0,1,0,1,1]]},
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{'dec' : digitalhf.viterbi39,
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'polys': [0x127, 0x19B, 0x1ED],
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'k' : 9,
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'taps' : [[1,1,1,0,0,1,0,0,1],
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[1,1,0,1,1,0,0,1,1],
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[1,0,1,1,0,1,1,1,1]]},
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{'dec' : digitalhf.viterbi48,
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'polys': [0xB9, 0x9D, 0xD3, 0xF7],
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'k' : 8,
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'taps' : [[1,0,0,1,1,1,0,1],
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[1,0,1,1,1,0,0,1],
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[1,1,0,0,1,0,1,1],
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[1,1,1,0,1,1,1,1]]}]
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for d in data:
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run_test(45, d)
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if __name__ == '__main__':
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main()
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