Re: [time-nuts] fts 4050 performance
What did the datasheet show for the 4050? For the standard tube: 0.01s 2 x 10^-10 1s 7 x 10^-12 10s 7 x 10^-12 100s5 x 10^-12 1000s 2 x 10^-12 1s 5 x 10^-13 10s 2 x 10^-13 In the short-term the resolution of the 53132 will limit the results. In the mid-term your 4050 will expose the limitations of the 3801. And in the very long-term the 3801 will expose the limitations of the 4050. Make sense? Yes, that makes much sense. I have 5370B, so maybe I will crank that up for somewhat better results on the short term measurements. I hope you plan to keep the experiment running so you can plot out to larger tau. I do and I will. Thanks much for the help. -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] fts 4050 performance
Attached is what I'm seeing in terms of adev and mdev on my new FTS 4050. The performance is worse than I had expected, as compared to the datasheet. I'm not 100% confident in my test setup, but I'm not seeing any obvious outliers in the data. Test setup is as follows: Counter: HP 53132A Timebase: external, 10MHz from Z3801A Start: 1 PPS from Z3801A, DC, 50Z, 2v5 trigger level Stop: 1 MHz from FTS 4050, AC, 50Z, auto trigger -ch fts4050ti_vsz38081a_pps_53132_z3801a_fref.png Description: PNG image ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] fts 4050 performance
Hi Chris: If the source of a pulse is 50 Ohms and it's TTL level at open circuit ( 0 to 5 volts) and the load is 50 Ohms, then when you connect a 50 Ohm load the pulse is 0 to 2.5 volts and so setting the trigger to 2.5 volts is just on the edge of not working. It's best to put a T connector and have a look with a scope. If the above is the case then a trigger level of 1.25 might work better. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Christopher Hoover wrote: Attached is what I'm seeing in terms of adev and mdev on my new FTS 4050. The performance is worse than I had expected, as compared to the datasheet. I'm not 100% confident in my test setup, but I'm not seeing any obvious outliers in the data. Test setup is as follows: Counter: HP 53132A Timebase: external, 10MHz from Z3801A Start: 1 PPS from Z3801A, DC, 50Z, 2v5 trigger level Stop: 1 MHz from FTS 4050, AC, 50Z, auto trigger -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] fts 4050 performance
Thanks for posting the plot. At first glance it looks close to OK. Remember what you are plotting is the RMS sum of stability and noise of three things: your FTS4050, your Z3801A, and your 53132A. Each of these three instruments will contribute for good or for bad at different ranges of tau. What did the datasheet show for the 4050? In the short-term the resolution of the 53132 will limit the results. In the mid-term your 4050 will expose the limitations of the 3801. And in the very long-term the 3801 will expose the limitations of the 4050. Make sense? For example, note that the ADEV is around 2e-10 at tau 1 s, which is just what you would expect for a counter with ~150 ps TI resolution. The 4050 and 3801 are much better but the counter limits your short-term measurements. The plot then follows a nice -1 slope for a couple of decades, as expected, until the averaged resolution of the counter catches up with the 4050 or 3801. By the time you hit tau 1000 s the counter is better than either the 4050 or 3801 and so what you are seeing is the true stability of the two standards compared together, no longer limited by the 53132. I hope you plan to keep the experiment running so you can plot out to larger tau. There are some FTS 4050 cesium plots here: http://www.leapsecond.com/museum/fts4050/ see log23031v.gif and log22421v.gif Also some HP Z3801A GPSDO plots here: http://www.leapsecond.com/museum/z3801a/ see log8286v.gif or log8550v.gif /tvb - Original Message - From: Christopher Hoover [EMAIL PROTECTED] To: time-nuts@febo.com Sent: Sunday, July 30, 2006 12:09 Subject: [time-nuts] fts 4050 performance Attached is what I'm seeing in terms of adev and mdev on my new FTS 4050. The performance is worse than I had expected, as compared to the datasheet. I'm not 100% confident in my test setup, but I'm not seeing any obvious outliers in the data. Test setup is as follows: Counter: HP 53132A Timebase: external, 10MHz from Z3801A Start: 1 PPS from Z3801A, DC, 50Z, 2v5 trigger level Stop: 1 MHz from FTS 4050, AC, 50Z, auto trigger -ch ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
