[time-nuts] Misbehaving FTS1050A

[Jim Schatzman]

Michael and Bob-

I thank you guys for your suggestions. I think that I have confused matters by not providing all the data to back up my assertions. In hopes that it will help, here is a bit more....

I have attached a couple more plots. These are instantaneous frequency measurements, made for the same pair of FTS1050A oscillators (including the notable #7), made with the same TSC5110A  DMTD instrument, made about a week apart.

You can see a number of small frequency jumps in the B plot.The MADEV for the "B" data is about twice that of the "A" data over much of the tau range. 

I have performed around 15 tests with #7. What I observe is that the behavior varies from test to test. I see this quirky behavior with #7 and with none of the other 16 FTS1050A and two FTS1150A oscillators in my lab. I haven't shown you all of the data so I can understand some skepticism. I hope that this pair of measurements will be more convincing. Same oscillator pair. Same measurement device. One week apart.

To be fair, I have in the past had trouble with a TSC5110A  DMTD. Its  internal 32 MHz  oscillator occasionally went dramatically off-frequency, messing up the measurements.These measurements were made with a different TSC5110A unit. I have also observed the bad behavior of #7 using a TSC5120A., which uses a different design.  So... I don't think we can ascribe the results to the instrument.

Jim



-------------- next part --------------
A non-text attachment was scrubbed...
Name: 3_vs_7_freqA.png
Type: image/png
Size: 25936 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20230430/30f04eee/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 3_vs_7_freqB.png
Type: image/png
Size: 25787 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20230430/30f04eee/attachment-0001.png>