GPSDO Testing and Excel Log - Page 1
Forum section: electronics / general

author: Zenwizard
author_rank: Regular Contributor
timestamp: May 09, 2024, 01:32:24 pm
content: I have been asked to if I was willing to do some stability testing on some of the cheaper GPSDO units that can be had from the auction site in the sky. I have started an excel sheet that is attached for some stability testing.Test equipment usedKeysite 53230A - Frequency counter no optionsStanford research FS725 - Rubidium clock for the 53230AGPSDO supplying 1PPS to the FS725frequency counter had a 24 hour warm up along with the GPSDO's under test10 Mhz reference had a grater then 3 month warmup time as it runs 24/7 in the lab. (Both the FS725 and the GPSDO)A link to the 10 Mhz reference playlist on YouTube is here -Excel file is attached.

author: erialor
author_rank: Newbie
timestamp: May 16, 2024, 02:33:01 pm
content: Thanks alot - I don't really have equipment for testing my equipment... (I have a version of their GPSDO with LCD - according to the LCD readout the 10MHz seems to be at max +/- 0.4 mHz - normally +/- 0.1 mHz)Do you happen to have the BG7TBL FA-3 Frequency counter and/or tested it? (or their FA-5?) - or the BG7TBL FDIS-5 OCXO Frequency Standard and/or tested it?Thanks for sharing.

author: Zenwizard
author_rank: Regular Contributor
timestamp: September 19, 2024, 01:41:15 pm
content: Updating the excel document with the LEO dual channel variable GPSDO

author: Wim13
author_rank: Frequent Contributor
timestamp: September 19, 2024, 04:44:48 pm
content: Why don't you use timelab, is more easy to see, see atach my measurements , reference is Efratom rubidiumAlso tested BG7TBL and both Leo Bodnar, you figures for 1 sec: 1,24E-11 and 10 sec: 6,3E-12 are almost the same,but your 100 sec has great difference.You can also read your samples from excel, via a txt file into timelab

author: testpoint1
author_rank: Frequent Contributor
timestamp: September 20, 2024, 01:41:48 pm
content: Hi, from your testing result, peak-peak value should select the maximum positive value minus the negative value during the testing period (1s, 10s or 100s), so the 100s should be more than 10s, since 100s include 10s already, but you select to average each sample ?

author: Zenwizard
author_rank: Regular Contributor
timestamp: September 23, 2024, 12:55:39 am
content: Samples were taking sequentially not in the same sample run. 100 averages for each gate time.Does time lab support 532xx counters? looks like it has the USB drivers for 531xx but I am curious if these will work with a 53230 Might have to try this some time soon.Pk-pk can diverge from ADEV especially at longer time intervals because of the oscillator correction during and update. Depending on the unit that can be a jumpy or a gradual process. Which one would depend on implementation.This is one of the reasons for GPSDO -> RB -> equipment. The movement of the RB unit is set for a time constant of 8+ hours. This causes the adjustments to be extremely slow which is good for instantaneous or short time scale measurements. It will also usually maintain a +/- 3 ns lock on the 1pps from the GPSDO. Once everything is stable.

author: Wim13
author_rank: Frequent Contributor
timestamp: September 23, 2024, 06:49:13 am
content: Tinmelab support lot of counters, all you need is a data stream, even from a txt file works.See attach list of standaard support counters