On Fri, 2011-04-29 at 15:42 -0400, Feng Andrew Ge wrote: > Nick, > > Could you confirm that switching TX frequency takes "a few ms"? How did > you get this number? Is it the same for switching TX frequency after > the code has been running for a while, that is, reconfiguring the TX > frequency dynamically?
We don't have a guaranteed spec for PLL settling time on the WBX, and we encourage users to experimentally determine the settling time for their particular setup and frequency. The figure I gave is based on what I've seen in the lab, to the best of my recollection. =) It should be pretty straightforward to determine the settling time for your setup and frequency step by taking a data capture of a known source. Any time you retune a PLL VCO, it will take some time to settle. If you need to avoid that settling time, you can do CORDIC-only tuning with the advanced tuning parameters to shift around within the bandwidth of your ADC. This will provide a basically instantaneous tuning speed within a range of 50MHz for USRP2/N2XX, or 32MHz for USRP1/E100. --n > > Andrew > > On 04/29/2011 12:00 PM, [email protected] wrote: > > Every time you tune the TX you'll have to wait a few ms for it to become > > stable. For voice transmission purposes, a few ms is effectively > > instantaneous anyway. And if you aren't retuning, then it will come up > > instantly, because the LO will still be running in between sample > > bursts. > > > > --n > > > _______________________________________________ Discuss-gnuradio mailing list [email protected] https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
