Re: [Discuss-gnuradio] Fractional resampler eats stream tags on changes on the "ratio" input

[Piotr Krysik]

W dniu 01.10.2015 o 14:46, Piotr Krysik pisze:
> W dniu 25.09.2015 o 23:23, Tom Rondeau pisze:
>
>
>
> Looking at the block, I was hoping it was as easy as putting a
> set_relative_rate call in the set_resamp_rate to adjust how the tags
> are being propagated. But it's not that simple. See Issue #846
> (http://gnuradio.org/redmine/issues/846) for details on the problem.
>
> Tom
>  
>
Hi,

I'm writing to let everyone know that resampling blocks after changing
the resampling rate in the run-time is still eating stream tags. This
makes some designs impossible to implement currently.

For example - it would be great if it was possible to implement a clock
offset frequency correction like I have drawn on the attached image:
-there are two blocks that do the correction: resampler and frequency
shifting block,
-they change their parameters (resamp_rate, frequency_shift) on stream tags,
-there is a block that does clock frequency offset measurements that is
connected at the end (putting it in different place is not practical in
many circumstances),
-these measurements are sent to frequency offset control block which
turns them into control messages addressed for both resampler and
frequency shifter,
-msg to tag blocks adds a tag containing a control message to a stream,
-the information about changes of settings of the resampler and rotator
are interpreted also by the measurement block, that adjusts measurements
based on this information.

But currently it not possible to do this due to the issue with the
resampling blocks.

Did you Tom or anyone found the source of the problem?   

Best Regards,
Piotr Krysik

frequency_offset_correction.png
Description: PNG image