Shape is a sinusoid. Vrms going into a 1 megaohm scope is 1.4V, so I would expect that to be ~.7V going into a 50 ohm load (the SDR), which I believe is under the max power requirement for the external reference of the N310.
-Chris On Tue, Sep 1, 2020 at 9:26 AM Marcus D Leech <[email protected]> wrote: > What are the output parameters of your Rb reference? Signal amplitude and > shape, etc. > > Sent from my iPhone > > > On Sep 1, 2020, at 11:18 AM, Christopher Flood via USRP-users < > [email protected]> wrote: > > > > > > Hi all, > > > > Sorry if this is coming through twice - I sent it once before I > subscribed to the list, but didn't know if it went through or not! (I > didn't see it in the archives...) > > > > ------- > > > > I'm having some trouble using an external reference with the Ettus N310. > The reference I am using is a FS725 Rubidium Frequency Standard. > > > > To test the difference between the internal clock and the external > reference, I transmitted a 10MHz signal from the Ettus N310 with and > without the external reference. Using just the internal clock of the SDR, > the 10MHz signal slowly wanders with respect to the 10MHz signal from the > Rubidium Frequency Standard as seen on an oscilloscope. This is to be > expected since the stability of the internal clock in the SDR is worse than > the Rubidium Frequency Standard. > > > > However, when I connect the 10MHz signal from the Rubidium to the > external reference of the N310 and tell the N310 to use the external > reference, the 10MHz signal that the N310 generates wanders much faster > with respect to the 10MHz signal from the Rubidium. This is opposite of > what I believe should happen, assuming the N310 is truly using the external > reference signal. > > > > Have any of you experienced this or have any tips as to what might be > going on? > > > > Thanks! > > > > -Chris > > _______________________________________________ > > USRP-users mailing list > > [email protected] > > > http://secure-web.cisco.com/1nWDwD0LbO77QthlIKVs0gyhEI4cVA_IfTj4rvvFSL4qWjw_BKsjarpNVGUg1WSCn9mLxWoszHiy1EL4wQBcyjVSZlchr4oAdnfbUKsQurDlSMkQ3xes5nNVfRZbMo1K_tC57_jfBijc7k1IJEeJI4eGE5lp6Hvxm5TrWP7xYZJN3Rno2PLqMojzmmGUON3j_FwZI5DrM1IRJJOp4zugqAiDWJkDCb9_EmunfDHehAlAUGJMMDQ9fvhujOQ6RMQSye2luXmluRt_L10jyNP6kk-a7ojOTF1lgm_5ZcB9LpYVMPx8JEbY8_VIcwrlrC-n2XC4dn41AUQyHPf47I3DWWUSBZZGaTEgad3YzhpIvd0Mk3XAPpGfdyAPTH6kEW-xpRHOSnTArwXMSBHYc-Wy_utBs6L16LMlPST1Q65z9FcHKQbE-3AjZkQbUl--HGEeSu2HcZH89_ufKsucuflnBKQ/http%3A%2F%2Flists.ettus.com%2Fmailman%2Flistinfo%2Fusrp-users_lists.ettus.com > >
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