I'm using the external 10 MHz input to my B210 and getting the following lock status messages: Waiting for "lo_locked": ++++++++++++++++++++ locked. Waiting for "ref_locked": _+____+____+____+___++ Here is the waveform of my 10 MHz clock ( I tried both AC coupled (yellow) and DC coupled (blue) ) the results are the same. [image: ac-coupled.png] Any hint what makes B210 unhappy will be greatly appreciated. What is the difference between LO lock status and REF lock status?

On 04/02/2018 12:17 PM, Sailor Jerry via USRP-users wrote: > I'm using the external 10 MHz input to my B210 and getting the > following lock status messages: > > Waiting for "lo_locked": ++++++++++++++++++++ locked. > Waiting for "ref_locked": _+____+____+____+___++ > > Here is the waveform of my 10 MHz clock > ( I tried both AC coupled (yellow) and DC coupled (blue) ) the results > are the same. > > ac-coupled.png > > Any hint what makes B210 unhappy will be greatly appreciated. > > What is the difference between LO lock status and REF lock status? > > The LO is the local oscillator on the synthesizer. Since the board has an always-on master clock that is *steered* by the external reference, I would expect that even with a flaky reference clock, the synthesizer would be able to lock. Your waveform looks rather "dirty", and it's at a level of only 1.1V or so? The B210 can tolerate up to 3.3V on the 10MHz input.

Great thanks Marcus, will try cleanup the input. Would is still work with 2 Vpp AC coupled input? On Mon, Apr 2, 2018 at 9:33 AM Marcus D. Leech via USRP-users < usrp-users@lists.ettus.com> wrote: > On 04/02/2018 12:17 PM, Sailor Jerry via USRP-users wrote: > > I'm using the external 10 MHz input to my B210 and getting the following > lock status messages: > > Waiting for "lo_locked": ++++++++++++++++++++ locked. > Waiting for "ref_locked": _+____+____+____+___++ > > Here is the waveform of my 10 MHz clock > ( I tried both AC coupled (yellow) and DC coupled (blue) ) the results are > the same. > > [image: ac-coupled.png] > > Any hint what makes B210 unhappy will be greatly appreciated. > > What is the difference between LO lock status and REF lock status? > > > The LO is the local oscillator on the synthesizer. Since the board has an > always-on master clock that is *steered* by the external reference, I would > expect > that even with a flaky reference clock, the synthesizer would be able to > lock. > > Your waveform looks rather "dirty", and it's at a level of only 1.1V or > so? The B210 can tolerate up to 3.3V on the 10MHz input. > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >

 On 04/02/2018 12:17 PM, Sailor Jerry via USRP-users wrote:

 I'm using the external 10 MHz input to my B210 and getting the
 following lock status messages:

 Waiting for "lo_locked": ++++++++++++++++++++ locked.
 Waiting for "ref_locked": _+____+____+____+___++

 Here is the waveform of my 10 MHz clock
 ( I tried both AC coupled (yellow) and DC coupled (blue) ) the
 results are the same.

 ac-coupled.png

 Any hint what makes B210 unhappy will be greatly appreciated.

 What is the difference between LO lock status and REF lock status?

 The LO is the local oscillator on the synthesizer.  Since the
 board has an always-on master clock that is *steered* by the
 external reference, I would expect
   that even with a flaky reference clock, the synthesizer would be
 able to lock.

 Your waveform looks rather "dirty", and it's at a level of only
 1.1V or so?  The B210 can tolerate up to 3.3V on the 10MHz input.



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On 04/02/2018 01:04 PM, Sailor Jerry wrote: > Great thanks Marcus, will try cleanup the input. Would is still work > with 2 Vpp AC coupled input? The spec says max +15dBm, which in a 50ohm system is 3.5V P-P. I suspect the main issue is that your waveforms are quite nasty, and likely contain unwanted harmonic content that is confusing the refclock PLL. > > On Mon, Apr 2, 2018 at 9:33 AM Marcus D. Leech via USRP-users > <usrp-users@lists.ettus.com <mailto:usrp-users@lists.ettus.com>> wrote: > > On 04/02/2018 12:17 PM, Sailor Jerry via USRP-users wrote: >> I'm using the external 10 MHz input to my B210 and getting the >> following lock status messages: >> >> Waiting for "lo_locked": ++++++++++++++++++++ locked. >> Waiting for "ref_locked": _+____+____+____+___++ >> >> Here is the waveform of my 10 MHz clock >> ( I tried both AC coupled (yellow) and DC coupled (blue) ) the >> results are the same. >> >> ac-coupled.png >> >> Any hint what makes B210 unhappy will be greatly appreciated. >> >> What is the difference between LO lock status and REF lock status? >> >> > The LO is the local oscillator on the synthesizer. Since the > board has an always-on master clock that is *steered* by the > external reference, I would expect > that even with a flaky reference clock, the synthesizer would be > able to lock. > > Your waveform looks rather "dirty", and it's at a level of only > 1.1V or so? The B210 can tolerate up to 3.3V on the 10MHz input. > > > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com <mailto:USRP-users@lists.ettus.com> > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com >