[time-nuts] CW12-TIM vs M12M and the world

[SAIDJACK at aol.com]

Hi guys,
 
I use one of our Fury's here with selected OCXO and M12M GPS for ADEV  
plots. The M12M data I quoted earlier was published in papers by CNS (links are  
in the time-nuts archives) as they were testing the M12 against USNO and 
LEA-6T  etc.
 
In terms of M12M versus M12+, we did not see much of a timing improvement,  
maybe a tiny bit. But there was a big improvement in GPS sensitivity, lock 
time,  thermal stability (this is probably the biggest improvement as they 
are using a  much better TCXO now), and lower power consumption.
 
Also, attached please find two plots of an FTS250 unit with TCXO, phase  
noise, and ADEV. This unit is now on Digikey for $687.
 
I will try to post longer ADEV data later. The unit was powered form a  
low-noise 3.3V regulator, and the three power pins were filtered with  
high-quality ferrites to avoid supply cross talk. Still the phase noise looks  
pretty ugly in my opinion. ADEV is not too bad for a TCXO, but even breathing on  
the unit will make it jump massively of course. Also note that they seem to 
 "jump" their TCXO from time to time by 10's of ppb, I specifically chose 
an ADEV  measurement where that did not happen, if it happens the ADEV plots 
go to  10E-09's or worse of course.
 
Bye,
Said
 
 
 
 
In a message dated 3/30/2012 13:20:12 Pacific Daylight Time,  
actast at hotmail.com writes:


Has  anyone compared the M12M to the M12+?
Thanks for all the input, it is  really appreciated.
best wishes;
Thomas  Knox



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