Gary- Interesting. The TICC is spec'ed to have a 10e-10 AD floor at 1 sec. Your measurement is slightly better than the spec. How can we know whether you are measuring the test source (JL GPSTLXO) or the stability of the TICC itself?
Jim At 03:10 AM 4/25/2018, you wrote: >Send time-nuts mailing list submissions to > time-nuts@febo.com > >To subscribe or unsubscribe via the World Wide Web, visit > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >or, via email, send a message with subject or body 'help' to > time-nuts-requ...@febo.com > >You can reach the person managing the list at > time-nuts-ow...@febo.com > >When replying, please edit your Subject line so it is more specific >than "Re: Contents of time-nuts digest..." > > >Today's Topics: > > 1. Re: Cheap jitter measurements (Gary E. Miller) > > >---------------------------------------------------------------------- > >Message: 1 >Date: Tue, 24 Apr 2018 20:45:08 -0700 >From: "Gary E. Miller" <g...@rellim.com> >To: time-nuts <time-nuts@febo.com> >Subject: Re: [time-nuts] Cheap jitter measurements >Message-ID: <20180424204508.5794f...@spidey.rellim.com> >Content-Type: text/plain; charset="utf-8" > >Time-nuts! > >I went ahead and bought the TAPR-TICC, it is a very impressive >instrument. For this setup it is combined with a Jackson Labs >GPSTLXO as the 10MHz reference. The JL is a GPS disciplined temperature >compensated crystal oscillator. > >The first setup uses the TAPR-TICC in Period mode, outputting the PPS >period individually for channel A and channel B. > >Channel A is the PPS of a plain u-blox NEO-M8N. Channel B is the >PPS of the JL GPSTLXO. > >Simple to get the cycle times from the USB serial port. > >Then I grabbed a copy of the easy to use Python Allantools. > https://github.com/aewallin/allantools > >A little coding later and there are nice plots. They were compared to >the output of tvb's adev.c program. Results are similar. > >Results are attached. gps.png is the plain NEO-M8N. GPSTLXO is the >JL part. > >gps.png looks as expected. GPSTLXO.png shows the quality of the JL part, >but does have some odd divots in the plot. Maybe artifacts of using the >PPS derived from the reference 10MHz? Or an artifact of the 10e6 divider? > >There are adev's of Rb standards here: http://www.ke5fx.com/rb.htm > >My guess is that the oadev at 1s would be about 50x better with >a Rubidium? But similar at 10k seconds? > >Comments? > >RGDS >GARY >--------------------------------------------------------------------------- >Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703 > g...@rellim.com Tel:+1 541 382 8588 > > Veritas liberabit vos. -- Quid est veritas? > "If you canât measure it, you canât improve it." - Lord Kelvin >-------------- next part -------------- >A non-text attachment was scrubbed... >Name: gps.png >Type: image/png >Size: 46884 bytes >Desc: not available >URL: ><http://www.febo.com/pipermail/time-nuts/attachments/20180424/871e2b90/attachment.png> >-------------- next part -------------- >A non-text attachment was scrubbed... >Name: GPSTLXO.png >Type: image/png >Size: 35622 bytes >Desc: not available >URL: ><http://www.febo.com/pipermail/time-nuts/attachments/20180424/871e2b90/attachment-0001.png> > >------------------------------ > >Subject: Digest Footer > >_______________________________________________ >time-nuts mailing list >time-nuts@febo.com >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >------------------------------ > >End of time-nuts Digest, Vol 165, Issue 48 >****************************************** _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
