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Re: [Discuss-gnuradio] Bug with scrambler in hierarchical block
From: |
Daniel Estévez |
Subject: |
Re: [Discuss-gnuradio] Bug with scrambler in hierarchical block |
Date: |
Tue, 14 Feb 2017 16:16:10 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 |
El 14/02/17 a las 15:46, Daniel Estévez escribió:
> Hi,
>
> I have a hierarchical block that implements a CCSDS synchronous
> (additive) scrambler/descrambler.
>
> I have noted that the scrambler doesn't reset properly. The first bit is
> wrong all the times except the first one. However, if I take all the
> block inside my hierarchical block and put them on a flowgraph,
> everything works fine. I'm puzzled.
>
> See the attached files. The hierarchical block is ccsds_descrambler.grc.
> The test flowgraph is test.grc. It contains both the "CCSDS descrambler"
> block and a set of blocks which is precisely what is inside the "CCSDS
> descrambler" block. By default, you see the output of the CCSDS
> descrambler. Note that the first time the first byte is 0xff but the
> remaining times it is 0x7f. However, if you disable one of the message
> debug blocks and enable the other one, you'll see that the first byte is
> always 0xff.
>
> I have no clue about what could be the problem.
>
> I'm running GNU Radio 3.7.10.1.
I've been doing some further tests and it seems that it doesn't have to
do much with whether the descrambler is implemented as a hierarchical
block or not.
In some other flowgraphs I have I've replaced the descrambler
hierarchical block by its "contents" and the problem with the first bit
being wrong after a reset persists.
Perhaps something about the scheduler?
Regards,
Daniel
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