What is the magnitude of the frequency drift?
What is the magnitude of the gain drift? What are you measuring backscatter *from*? On 2014-11-28 10:14, khalid.el-darymli via USRP-users wrote: > Hi, > > Given a set of synced _(i.e., using external GPS REF/PPS)_, time-commanded > and calibrated _(i.e., through compensating for the phase/mag offset between > digital Tx chirp prior to transmission and ADC'ed Rx signals) _N200 devices > with LFTX/LFRX daughterboards, that work with coherent LFMCW chirps, I am > still seeing a tiny drift (both in the magnitude and frequency) of the > calibrated back-scatter Rx chirp received at time t1 when compared to an Rx > chirp received at an earlier time t0. > > The more the N200 device runs (e.g., 5 hours), the greater the drift is. > Obviously, this drift is pertinent to both the DAC and ADCs and the GPS > referenced clocks of the N200 devices. > > My questions are: > > 1- Why I still see such drift although my devices are synced with an external > GPS? and how do I correct for it? > > 2- Can the PLL CARRIER TRACKING block in GRC be used to track and correct for > such a drift? If so, how do I set the max/min freq inputs for this block? > > 3- Can AGC2 or AGC3 block be useful in this regard? If so, are there any > examples to explain how the input parameters of these blocks can be set up? > > Thanks. > > Best regards, > Khalid > > _______________________________________________ > USRP-users mailing list > usrp-us...@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com [1] Links: ------ [1] http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com
_______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org https://lists.gnu.org/mailman/listinfo/discuss-gnuradio
