Did you make sure the cal signal was turned on?? You can turn it
off on the E4401B.
On 3/30/2019 1:39 PM, Michael Williams
wrote:
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Hi Mark,
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Thanks for the reply and the thoughts.
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From the info in my CLIP, the 50 MHZ CAL
signal is generated by dividing the 800 MHZ 2nd LO
by 16.? The 2nd LO gets its power from the TEST MUX
(U56).? This mux is dead ¨C no enable signal, no activity on
any of the control lines.? That¡¯s where I¡¯m stuck, I can¡¯t
figure out if it¡¯s a hardware or software issue that is
causing the 2nd LO to not get turned on.? The CLIP
is not very clear on what tells the fractional divider (U55)
to enable it.
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The 10MHz reference clock is the timing
source for the 800 MHZ 2nd LO, and is present, both
internally and at the 10MHZ output connector in the back.
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Thanks again,
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Mike
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