[time-nuts] Help with my ADEV measurement setup
watsondaniel3 at gmail.com
Tue Jun 30 20:05:20 EDT 2015
I tried both the PPS and the 10MHz signal on channel 1, with the 10MHz DUT
on channel 2. Tom emailed me and it turns out the software was not
detecting the units correctly from the serial string. (What are 6 powers of
ten between friends, right? :) ) Likely a settings mistake on my part, I
sent him a screen cap to see what's up.
None the less, I manually enter the time units and was able to plot some
data. I attached a new screen cap. How does this look?
On Tue, Jun 30, 2015 at 5:36 PM, Bob Camp <kb8tq at n1k.org> wrote:
> Are you using a PPS as the “start” and the 10 MHz as the “stop” or
> comparing two PPS signals?
> > On Jun 30, 2015, at 2:47 PM, Dan Watson <watsondaniel3 at gmail.com> wrote:
> > Hi,
> > I'm trying to take some ADEV measurements with my 53131A, and I'm having
> > some issues. This is my setup:
> > - 53131A with the OCXO option. Calibrated against a T-bolt. I also did
> > TI Quik cal and it passed
> > - I'm using RS-232 out with a null modem cable into a Serial-USB
> > - Software is TimeLab in talk-only mode. 53131A check box is checked.
> > - The counter is in TI mode, with a T-bolt on Channel 1 and DUT on
> Channel 2
> > - A delay of 1 second is set on the counter. TimeLab seems to accurately
> > detect this interval
> > I started measuring various devices, and could never seem to get better
> > than around 1x10^-6. Even my Rb was showing a 1 second ADEV of 10^-6.
> > Finally I put the T-bolt on channel 1 with common mode on to both
> > and it still measures around 10^-6. A picture of that is attached. Surely
> > this can't be right.
> > I tried frequency mode and it gives ADEVs of 10^-12 on the Rb and T-bolt,
> > as expected. I understand the issues with filtering that the 53131A does
> > internally on this mode, but at least it shows my setup is working to
> > degree. It's TI mode that seems to be wonky.
> > I'm probably doing something really stupid.
> > Thanks for any help you all can suggest.
> > Regards,
> > Dan W
> > <adevtest.png>_______________________________________________
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