|Subject:||Re: [Discuss-gnuradio] unexpected underruns|
|Date:||Wed, 2 Aug 2017 09:57:19 +0200|
|User-agent:||Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1|
Huh, I really don't know what's happening there :/ I sadly don't have the USRP to test this live with me right now, but there's absolutely no timed commands involved¹
So, trying to weed out bugs:
* I've replaced the USRP sink with a "Probe Rate" block,
connected to a "Message Debug"'s print port. I saw samples fly by
with more than 7 MS/s, so there really shouldn't be a bottleneck
here – can you try to do the same and see whether your system can
get similar rates? 7MS/s is still far too little for my taste, but
that is FM-Modulation-limited²
¹ "timed commands" are a USRP feature that allows certain things to happen at well-defined times. You get an L when a timed command reaches the USRP after the specified time has already passed. In your flow graph, all that could happen is that a sample packet reaches the USRP after it should – but that's unlikely, you'd get a "U" instead.
² at least on my machine, most of the time is spent in the FM modulator. Which is kind of annoying, because looking into that, what costs most time is the "keeping the phase within 0;2pi" floating point modulo operation. I might get the urge to fix that.
On 08/01/2017 08:31 PM, Rui ZOU wrote:
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