[time-nuts] Query about 5061B

[Jim Schatzman]

Time Nuts-

I think I posted an earlier version of this plot once before, which is ADEV for 7 different 5061B units. I accidentally tested unit #4 once with the cesium beam turned off and noticed a huge improvement in ADEV below tau = 500 secs. 
I am wondering about the feasibility of improving the short time stability by increasing the time constant of the control circuit (A9 board). Looking at the schematic, there appears to be an 8 uf capacitor C2 which limits the bandwidth of the control amplifier. The input impedance in Oper is 100K, implying an RC time constant of 0.8 second. 

I expect that adding some capacitance could make an improvement.  Has anyone tried this?   Any recommendations for the specific type of capacitor to use?

While investigating, I note that the schematic shows a "LTC" position for S2. I didn't actually try that and I am going to do so.  I never realized what that meant!  The input circuit has R5 (Oper position) @ 100K and R6 (LTC) @ is 12M). A factor of 120!!

Thanks-
Jim


Emacs!

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