[USRP-users] Passing arguments to an RFNOC block

Jonathon Pendlum jonathon.pendlum at ettus.com
Wed Feb 27 22:19:49 EST 2019


Hi Paul,

Your Nocscript has an error on line 47, you are a missing a comma:
LE($config 1) should be LE($config, 1). That may not be the source of your
issue, but try fixing that first.

Jonathon

On Thu, Feb 28, 2019 at 1:14 AM Paul Boven via USRP-users <
usrp-users at lists.ettus.com> wrote:

> Hi everyone,
>
> As part of the VLBI[1] backend that I'm making in RFNOC, my first step
> is to make a rational resampler. It takes the 100MS/s signal from a
> TwinRX, and reduces it to 80MS/s. This can be done with a 5:4 resampler.
> In order to make this work, I'm using the axi_rate_change block.
>
> Although the block works in simulation, I keep running into problems
> with the GRC integration, in particular SWIG throwing run-time errors.
>
> The problem seems to be in the way that the arguments (N, M, config) are
> passed around, but studying other blocks like the DDC block hasn't
> provided the clues for me to get past this hurdle.
>
> The resampler itself does work, which I tested by having it emit zeroes
> instead of the 'deleted' samples, and using a 'keen 1 in N' in GRC itself.
>
> At the moment, the block exits in VLBI_swig.py in set_arg:
> return _VLBI_swig_resamplerd5x4_sptr_set_arg(self, *args)
> RuntimeError: SyntaxError: Parsing Stopped at: $N, 5)
>
> If you're familiar with RFNOC, can you please have a look at:
>
> http://www.jive.nl/~boven/rfnoc-VLBI
>
> It contains the source, and also a compiled bitfile for the X310 for
> your convenience (but use at your own risk, of course).
>
> Regards, Paul Boven.
>
> [1] Very Long Baseline Interferometry
>
> _______________________________________________
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> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
>
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