[USRP-users] UHD: What do the tx_metadata_t burst parameters mean?

Martin Braun martin.braun at ettus.com
Mon Apr 20 14:04:29 EDT 2015


Raj,

there is the docs on the structs themselves, plus the page I sent you.

Cheers,
M

On 18.04.2015 12:32, Raj Bhattacharjea via USRP-users wrote:
> Thank you for the references. Those examples give me a vague idea of
> what these concepts mean. I certainly can't say I have a precise
> definition, or understanding of how the behavior of UHD and/or the USRP
> will change with different uses of the burst parameters. I'll carry on
> by experimentation with the code and delving into the UHD source. I was
> hoping that there was documentation, but it appears that there is not.
> 
> On Tue, Apr 14, 2015 at 3:27 PM, <mleech at ripnet.com
> <mailto:mleech at ripnet.com>> wrote:
> 
>     __
> 
>     I'd suggest looking at the source for tx_timed_samples.cpp and
>     tx_bursts.cpp to get a feel for how this works, as well as
>     tx_waveforms.cpp
> 
>      
> 
>      
> 
>      
> 
>     On 2015-04-14 15:00, Raj Bhattacharjea via USRP-users wrote:
> 
>>     What is the meaning of various tx_metadata_t fields in UHD? The
>>     documentation is here:
>>      
>>     http://files.ettus.com/manual/structuhd_1_1tx__metadata__t.html
>>      
>>     This is API documentation explaining what functions and fields
>>     exist, but it does not tell me much about the concepts this API is
>>     implementing. Is there some document I'm missing that explains the
>>     concepts of metadata in UHD, how it is used, and what terms like
>>     time_spec and start_of_burst mean, precisely? When should a burst
>>     be considered to start? To stop? If I send 20 pulses of a carrier,
>>     each 20 microseconds long and separated by 10 microseconds, then
>>     sleep for 1 second, then do it again, do I have one burst per
>>     second, or 20? What difference does this metadata even make, the
>>     samples still go out the TX port regardless of these flags, right?
>>     If I don't use the burst start and stop metadata correctly, will
>>     the state of the USRP be somehow invalid when I go to TX again
>>     later in my application?
>>      
>>     -- 
>>     Raj Bhattacharjea
>>     Georgia Institute of Technology
>>     School of Electrical and Computer Engineering
>>     http://www.prism.gatech.edu/~gtg037s/
>>     404.894.7516 <tel:404.894.7516>
>>
>>     _______________________________________________
>>     USRP-users mailing list
>>     USRP-users at lists.ettus.com <mailto:USRP-users at lists.ettus.com>
>>     http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> 
> 
> 
> 
> -- 
> Raj Bhattacharjea
> http://www.prism.gatech.edu/~gtg037s/
> 
> 
> _______________________________________________
> USRP-users mailing list
> USRP-users at lists.ettus.com
> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
> 





More information about the USRP-users mailing list