Calvin,
does that mean the YTO is unlocked during the sweep?
Tobias
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-------- Original message --------
From: "Calvin Guan guancalvin@... [hp_agilent_equipment]"
Date: 10/16/17 00:20 (GMT+01:00)
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: 8568B YTO unlocked
?
On my 8566b, if the span is greater than certain MHz, the sweep source is operate in “Lock and Roll” mode - locks to the sweep start frequency then applies a ramp to roll.
Calvin
?
I don't know about the screen flickering, but I do think the YTO loop behavior is normal. At wider spans it is not constantly phase-locked - it is driven open-loop with fairly accurate sweep current, and I think possibly re-phase-locked just at the beginning
of the sweep each time around. For wide spans, you can't resolve the small frequency error on-screen anyway, but for narrow ones, more stability is needed, so the LO is locked. It's also possible that the narrow spans instead fix the first LO and use the second
LO for sweeping - I can't recall for sure, but it should be one of those two schemes.
Definitely get the manual if you haven't already.
Ed
