W dniu 25.09.2015 o 23:23, Tom Rondeau pisze: > On Wed, Sep 23, 2015 at 4:06 PM, Piotr Krysik <per...@o2.pl > <mailto:per...@o2.pl>> wrote: > > Hi all, > > Fractional resampler has additional "rate" signal input for supplying > resampling ratio for each input signal sample. > Changes of the signal on the "ratio" input might result in loss of > tags > that are close in time to these changes. > > I observed the problem when I was implementing frequency offset > corrector (attached flowgraph screenshot). > Short description what is going on there: > -when message comes to ppm_in port of the block "Controlled const > source" changes value of constant at the output, > -when Controlled rotator observe this change on its input, it emits > stream tag, > -for changes of about +/-50ppm (and above) on the 'ratio' input of the > Fractional Resampler, tags coming from the Controlled rotator are not > going through. > > Just by looking at the Fractional Resampler implementation > > (https://github.com/gnuradio/gnuradio/blob/master/gr-filter/lib/fractional_resampler_cc_impl.cc#L104) > I'm not able to locate source of the problem. > > I can implement minimal working example if needed. > > Best Regards, > Piotr Krysik > > > Piotr, > > 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 Tom,
Thank you for the response and time spent on debugging this issue. Now when I know what is going on I can try to prepare some workaround for my purposes (i.e. single C++ block for frequency offset correction). Best Regards, Piotr _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
