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I have implemented a loopback flowgraph intending to perform the following:

  1. FEC encode (repetition code) an input stream in16_2.dat
  2. Store the encoded stream as out16_2_fec_async_enc.dat
  3. FEC decode the encoded stream and store it as out16_2_fec_async_dec.dat

Follows the implemented flowgraph:

enter image description here

My expectation: I was hoping that out16_2_fec_async_dec.dat would be equal to in16_2.dat.

What really happened: out16_2_fec_async_dec.dat was empty. I can confirm that the encoded data, out16_2_fec_async_enc.dat, is apparently correct, by running:

$ xxd -b in16_2.dat
00000000: 00000000 00000000 11111111 11111111 01010101 01010101  ....UU
00000006: 10101010 10101010

$ xxd -b out16_2_fec_async_enc.dat
00000000: 00000000 00000000 00000000 00000000 00000000 00000000  ......
00000006: 00000000 00000000 11111111 11111111 11111111 11111111  ......
0000000c: 11111111 11111111 11111111 11111111 00001111 00001111  ......
00000012: 00001111 00001111 00001111 00001111 00001111 00001111  ......
00000018: 11110000 11110000 11110000 11110000 11110000 11110000  ......
0000001e: 11110000 11110000                                      ..

Also, the confirmation that out16_2_fec_async_dec.dat is empty:

$ xxd -b out16_2_fec_async_dec.dat

I wonder what may be missing in this setup?
Please let me know if additional information is needed.
Thank you in advance!

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The issue is that the FEC Async Decoder expects the input to be soft decisions with one decision per item instead of packed PDUs.

Here's a working example:

enter image description here

Encoder deployment:

  • Packed: yes
  • Rev. unpacking: yes
  • Rev. packing: yes

Repack Bits:

  • Packet alignment: Output
  • Endieness: LSB

Decoder deployment:

  • Packed: yes
  • Rev. packing: yes
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