[time-nuts] question Alan deviation measured with Timelab and counters

steph.rey steph.rey at wanadoo.fr
Fri Jan 9 06:53:36 EST 2015

 Dear all,

 I'm trying to measure Alan Deviations using Timelab and some frequency 
 The device under test is a GPSDO using a TCXO as référence

 I've an HP58503B GPSDO which feeds my counters. I've tried an HP5342A, 
 0-18 GHz, 1 Hz resolution and a Philipps PM6654C, 0.01Hz resolution.

 In Timelab, the plot with the HP5342A is around 10e-7 which correspond 
 to 1Hz and with the PM6654C, the plot is around 10e-10.
 I would suspect that this is still the counter which limits the actual 
 response of my device under test.

 My question are :
 - how to measure Alan Deviations with levels below 10e-12/10e-13 ? What 
 can be the application of measurement Alan deviation > 10e-10 ? I guess 
 most of the low frequency
 - The HP53503 GPS is given to be 10e-11 / 10e-12. I guess this will 
 limit anyway the measurement floor. I've a Rb source, but it's stability 
 is within the same range. What kind of reference would be more suitable 
 for such measurements ?
 - With the PM6654C on 15h measurement, I can see some frequency jumps 
 of 800 Hz which are not relevants with the GPSDO undertest. I suspect 
 error in data transmission. This makes the overall measurement totally 
 wrong (10e-5). The counter is in talk only mode. I'd like to get rid of 
 these points maybe 40-50 points out of 10000. Is there a way to do that 
 from Timelab or the only option is to export the file and process 
 manually the data ?

 Thanks & cheers

More information about the time-nuts mailing list