gnuradio.gr: Information Coding and Decoding

gnuradio.gr.additive_scrambler_bb(int mask, int seed, int len, int count = 0) → gr_additive_scrambler_bb_sptr

Scramble an input stream using an LFSR. This block works on the LSB only of the input data stream, i.e., on an “unpacked binary” stream, and produces the same format on its output.

The scrambler works by XORing the incoming bit stream by the output of the LFSR. Optionally, after ‘count’ bits have been processed, the shift register is reset to the seed value. This allows processing fixed length vectors of samples.

Parameters:

• mask – Polynomial mask for LFSR
• seed – Initial shift register contents
• len – Shift register length
• count – Number of bits after which shift register is reset, 0=never

gnuradio.gr.descrambler_bb(int mask, int seed, int len) → gr_descrambler_bb_sptr

Descramble an input stream using an LFSR. This block works on the LSB only of the input data stream, i.e., on an “unpacked binary” stream, and produces the same format on its output.

Parameters:

• mask – Polynomial mask for LFSR
• seed – Initial shift register contents
• len – Shift register length

gnuradio.gr.diff_decoder_bb(unsigned int modulus) → gr_diff_decoder_bb_sptr

y[0] = (x[0] - x[-1]) % M

Differential decoder

gnuradio.gr.diff_encoder_bb(unsigned int modulus) → gr_diff_encoder_bb_sptr

y[0] = (x[0] + y[-1]) % M

Differential encoder

gnuradio.gr.fake_channel_encoder_pp(int input_vlen, int output_vlen) → gr_fake_channel_encoder_pp_sptr

pad packet with alternating 1,0 pattern.

input: stream of byte vectors; output: stream of byte vectors

gnuradio.gr.fake_channel_decoder_pp(int input_vlen, int output_vlen) → gr_fake_channel_decoder_pp_sptr

remove fake padding from packet

input: stream of byte vectors; output: stream of byte vectors

gnuradio.gr.map_bb(__dummy_3__ map) → gr_map_bb_sptr

output[i] = map[input[i]]

gnuradio.gr.scrambler_bb(int mask, int seed, int len) → gr_scrambler_bb_sptr

Scramble an input stream using an LFSR. This block works on the LSB only of the input data stream, i.e., on an “unpacked binary” stream, and produces the same format on its output.

Parameters:

• mask – Polynomial mask for LFSR
• seed – Initial shift register contents
• len – Shift register length