Just in: Agilent 53132A with Opt 010; tested with Rubidium reference?!?! - Page 1
Forum section: electronics / testgear

author: bsodmike
author_rank: Regular Contributor
timestamp: May 31, 2021, 09:24:01 am
content: Hi all,I just received this Agilent 53132A after sitting for 2-months with local customs. I hooked up my FE-5680A Rubidium reference and with a gate time of 1s, I'm getting a reading of 10.000,000,117,7 Mhz.I am reading this as 117.7Hz greater than 10Mhz. Do I need another Rubidium reference to act as a tie-breaker?Thanks!

author: Yansi
author_rank: Super Contributor
timestamp: May 31, 2021, 09:44:19 am
content: That is not 117 Hz above, that is 0.117 Hz above. I would not even care about it. It is spot on already.

author: bsodmike
author_rank: Regular Contributor
timestamp: May 31, 2021, 10:12:01 am
content: Quote from: Yansi on May 31, 2021, 09:44:19 amEek yes, I miscalculated that, thanks! 0.000000117*(10^6) Doh!!Should I still consider running the Rubidium reference's signal into the Frequency counter's ExtRef? I also have a GPSDO reference.

author: Yansi
author_rank: Super Contributor
timestamp: May 31, 2021, 10:24:37 am
content: As far as I know, rubidium wears out with time. So unless you can really get use of the added benefit of it, I would just run the GPSDO.(I thought it was always good to at least have all instrumentation synced to a common reference, whatever it is.)

author: bsodmike
author_rank: Regular Contributor
timestamp: May 31, 2021, 01:38:10 pm
content: Exactly, at least I can use this as a reference and replace the Rubidium reference as needed down the road.Thanks for the advice, appreciated

author: dl1640
author_rank: Regular Contributor
timestamp: June 01, 2021, 03:07:42 pm
content: Some rubidium can also be linked to GPSDO, normally a GPSDO outperform a standalone rubidium at long-term stability, however it is always good if you compare your GPSDO with other's such as NMI's clock.Quote from: bsodmike on May 31, 2021, 10:12:01 am

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 01, 2021, 07:53:58 pm
content: Quote from: bsodmike on May 31, 2021, 09:24:01 amNo.A Rb standard usually has about 100 times better uncertainty than an OCXO, as both are once adjusted.Both references need several days to stabilize, though. They both are intended to let them run continuously. This is the case for the OCXO, if you let your 53132A always plugged in.Your Rb standard urgently needs a proper cooling plate, see manual. Otherwise it will soon die from over heating. Maybe you should assemble it into a proper case, together with a clean PSU, to let it also run continuously.The 10-8deviation sounds as if you compared w/o sufficient warm-up times.An OCXO may reach about 10-9deviation and stability from nominal, after about 48h , an Rb about 10-11after 2..5 days, depending on the model used, see specifications.To decide, whether one of those is completely off, you need to investigate on their histories. If you know, that you once have adjusted your Rb to these 10-11, e.g. by means of a GPSDO, you simply should trust your Rb reference.Another Rb standard poses the very same problems of insufficient warming up and/or unknown adjustment history.Frank