Re: Tuning latency of DBSRX2 for frequency hopping
Josh Blum <josh <at> ...> writes:
> On 10/04/2012 05:16 AM, sam wrote:
> > Hello Josh,
> > I am using WBX over USRPE110,
> FYI... This subject is DBSRX2, which in this case, DBSRX2 I2C based
> control, and I2C needs a lot of 2-way control and ACKing. So my advice
> is for WBX/SBX...
> > I want to test the Tuning latency using usrp->set_center_freq(freq).
> > For that, I surrounded the command with tic-toc. I got the latency around
> > microsecond.
> I highly recommend you try the master branch of UHD if you havent. The
> E100 now has the same fifo control interface as the N210s.
> What this means is not only timed commands, but things like tuning the
> WBX should queue up a bunch of commands ASAP w/o needing to ack.
> > - Is it a good way to test the over all latency?
> There is a example app in host/examples/ to measure turn around time. We
> should also have a nice wiki page on this soon on account of the GR Conf
> 2012 presentation.
> > - I think its huge latency, as I read in previous threads, you mentioned its
> > around 300 microsecond?
> The worst case lock time is 300us, after the commands arrive. Thats not
Thanks Josh for your reply, I got it now, that timing the command is timing
bunch of commands all together, and the time I got is the delay from all these
I am trying retune WBX Rx frequency and continue streaming with max delay of
1500 us, and 45 MHz separation (mainly listening to downlink and uplink GSM
channels). I read that WBX has single Rx front-end chain, so the only solution
would be to keep hopping between these channels (with 45 Mhz separation).
My question is, does the streaming continue directly after the lock time (300
us) ? or there are other dependencies to start streaming ?