Re: [Discuss-gnuradio] inband timestamp issues

[George Nychis]

> George,
>
> The timestamp semantics that we are using on the USRP2 is that for Rx,
> the timestamp refers to the time that we clock the sample out of the
> DSP Rx pipeline (n.b., not the Rx FIFO).  For transmit, it's the time
> we clock the sample into the TX pipeline (not the Tx FIFO).  In both
> cases, the reference point is at the edge of the DSP pipeline.  This
> seems to be the only place that makes sense, since the group delay
> through the pipeline varies depending on the configuration.  In all
> cases, the timestamp is in ticks of the master clock.

This sounds correct.  I think the major issue is just that the current 
implementation is taking the time the packet is built as the timestamp. 
 This is far from correct.  Because of this, we don't have a timestamp 
that represents the first or last sample, and if the packet builder is 
halted then we get these timestamp "jumps."

- George