Think you may be a bit too critical. IMO, they are talking about rapid drift - it generally is not stable equivalent to lock. The 6.15 end is always a bit more difficult. Generally, I switch back and forth between 2.3 and 6.15 and if the first 5 digits agree, I'm good.
If you think there is a problem, once you get it reasonably adjusted, close the PLL and watch the control voltage - if it is significantly unstable, maybe you do have a problem.
Also, I'd take a look at the voltages to see if the remain on target. If they do and you can get the frequency to remain relatively closse, you should be OK.
Cheers!
Bruce
Quoting Matt Huszagh <huszaghmatt@...>:
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I'm currently performing the YTO Main Coil driver adjustments (preferred
procedure) for my HP 8566B. This apparently sets the frequency endpoints
of the YIG. Leaving out some details, the procedure basically has you
key in zero spans centered at 2.3 and 6.15 GHz, disconnect the YTO loop
phase detector output and check the frequency of the 1st LO output.
I've performed this procedure probably 2 or 3 times in the past, and
each time I've found it difficult. The documentation says to wait for
the 1st LO output frequency to stabilize when adjusting the trimpots to
get the 2.3 and 6.15 GHz frequencies on mark (within 100 kHz). However,
I've always found the frequency to slowly drift in one direction. This
time I was able to get a pretty stable reading on the 2.3 GHz endpoint,
but the 6.15 GHz endpoint has been steadily drifting up over the last
10+ minutes. This long drift period obviously makes the procedure
difficult because you can't just adjust and check, you have to try to
predict where it will go.
Does anyone have any advice for how to perform this adjustment
effectively? There's an alternate procedure which I'm tempted to try.
Thanks
Matt
