The packetization happens in the radio_core (which is in noc_block_radio_core) in a block called rx_control_gen3. That is where the timestamp is applied. The output of that module goes to AXI Wrapper, which doesn't do much since rx_control_gen3 generates the header too.
If you want to resample, consider using axi_rate_change. That is a module I wrote to make N/M resampling easier. It handles things like EOB and timestamps automatically. We use it in the DDC and DUC blocks. On Wed, Jul 12, 2017 at 10:03 AM, Jason Matusiak < [email protected]> wrote: > Howdy Jonathon! > > Is a "packet" determined before or after the RFNoC stage of the chain (I > assume before since it is in the radio core)? > > Is there anyway to modify things if I decide to resample in an RFNoC > block? It seems like it would throw off the timing since the sample rate > into the block != the sample rate leaving the block in this case. > > ~Jason > > > On 07/12/2017 12:58 PM, Jonathon Pendlum wrote: > > Hey Jason, > > The timestamp of each packet describes the time the first sample in the > packet was received. The timestamp is based on a counter in > noc_block_radio_core (timekeeper.v.) that increments at the sample rate > (i.e. radio_clk). The time is relative to that counter's placement in the > processing chain. We do not do anything to back out the delays from > elements in front of the counter, such as the delay through the front end > filters, ADC, digital I/Q correction, etc. > > Jonathon > > On Wed, Jul 12, 2017 at 9:20 AM, Jason Matusiak via USRP-users < > [email protected]> wrote: > >> I have a timing question that has me going in circles, I don't understand >> how the USRP timestamps work when using RFNoC. >> >> In a normal system, packets have timestamps with them (or at least the >> first one does) and you can compute the time of any samples based on the >> timestamp, sample rate, and number of samples since the timestamp, right? >> >> Now, if I am using RFNoC, the timestamps aren't attached to the samples, >> right? Where does that timestamp get associated: Further down the stream? >> >> _______________________________________________ >> USRP-users mailing list >> [email protected] >> http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >> > > >
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