Hi Ekko, CCSDS27 is really old. In fact, it was really just discussed hours ago to remove it from future versions of GNU Radio; so if you feel like it might not be the right FEC for your application, feel encouraged to use other stuff! However, there's two things happening to your source:
1. Four byte offset: >From the decoder documentation: > This block is designed for continuous data streaming, not packetized > data. The first 32 bits out will be zeroes, with the output delayed > four bytes from the corresponding inputs. 2. half your bits are interepreted as erased bits. For that, decoding performance is not half bad: > The input is a stream of (possibly noise corrupted) floating point > values nominally spanning [-1.0, 1.0], representing the encoded > channel symbols 0 (-1.0) and 1 (1.0), with erased symbols at 0.0. But you're feeding it 0 and 1 instead of -1 and 1 ! So, use a scale=2 in your char_to_float, and add_const -1 Best regards, Marcus On 30.05.2016 05:58, Ekko wrote: > hello all > i want to use CCSDS 27 encode/decode ,so i write a grc to test these > two block without hardware, > but i got he dest data is not same with the source data, > so is there some wrong in my grc. > > these is the source file and dest file in my grcand my grc file > > thank you > > --Ekko > > > _______________________________________________ > Discuss-gnuradio mailing list > [email protected] > https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
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