Hi Your OCXO and the TBolt *should* be down around 1x10^-11 to 1x10^-12 at one second. That’s a factor of 10 to 100X better than the 53131 can do at a random frequency. At exactly 10 MHz it may be even worse than that. Effectively what you will be doing is measuring the noise floor of the counter out to a few hundred seconds. To get useful data, plan on runs of at least several hours, if not a few days.
Bob > On Jun 30, 2015, at 8:05 PM, Dan Watson <[email protected]> wrote: > > 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? > > Thanks > > Dan > > On Tue, Jun 30, 2015 at 5:36 PM, Bob Camp <[email protected]> wrote: > >> Hi >> >> Are you using a PPS as the “start” and the 10 MHz as the “stop” or >> comparing two PPS signals? >> >> Bob >> >>> On Jun 30, 2015, at 2:47 PM, Dan Watson <[email protected]> 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 >> the >>> TI Quik cal and it passed >>> - I'm using RS-232 out with a null modem cable into a Serial-USB >> converter >>> - 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 >> channels, >>> 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 >> some >>> 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>_______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > <adevplot_PPS.png>_______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
