[time-nuts] 10MHz LTE-Lite

[SAIDJACK at aol.com]

Hello Mike,
 
attached is a 10MHz DIP-14 TCXO Phase Noise plot from a random  LTE-Lite 
unit.
 
I had sent out a 20MHz typical phase noise plot some weeks ago, and  
comparing the two they are almost perfectly 6dB apart as would be expected from  
the 20log(n/m) relationship. There are variations from unit to unit of 
course,  but it does not seem like one version of the board or the other has 
advantages  in terms of phase noise.
 
I had also sent out a superimposed plot of the 20MHz and the divide-by-2  
10MHz output of the same board at that time, and again the relationship was  
almost perfectly 6dB lower at 10MHz versus 20MHz.
 
While phase noise follows theory, it does seem that the DIP14 metal shield  
has a beneficial effect on the ADEV stability though. The plots we are 
getting  are pretty darn good, and I want to test more boards before I post any 
ADEV,  because its quite a bit better than our specification and I want to 
make sure  its real.
 
The 10MHz DIP-14 boards do not have an isolating buffer like the 20MHz  
boards do, on these the TCXO drives the output directly, so one must be careful 
 to set the equipment to 1M Ohms input impedance or use a buffer 
externally,  which is what we did to measure the attached PN plot.
 
Bye,
Said
 
 
 
 
In a message dated 11/20/2014 13:48:22 Pacific Standard Time,  
n1jez at burlingtontelecom.net writes:

Hi  Said,

Have you ever done a phase noise comparison of the 20 MHz TCXO  divided 
by 2 and the 10 MHz TCXO version?

My unit has only been  powered for a few hours for initial tests. I'm 
using the uBlox U-Center  software version 8.12 for monitoring the GPS.

Mike

On 11/20/2014  3:32 PM, S. Jackson via time-nuts wrote:
> Hello  everyone,
>
> after what must have been the longest thread in  T-nuts history its  
almost
> all quiet today. I am going to take  advantage of that and  announce some
> good news:
>
>  Its a miracle: the 10MHz DIP-14 TCXOs for the LTE-Lite came in weeks   
ahead
> of schedule from the factory! And they work very  well.
>
> We will thus be shipping out the 10MHz LTE-Lite eval  boards in the  next
> couple of working days. There are still a  number left for sale on Ebay
> (search for "LTE Lite GPSDO"), so if you  were hesitant to get one due to 
the  long
> lead-time, then now is  your chance.
>
> Also, after being in time nuts hands for almost a  week I am surprised
> there are very few mails, questions, or comments  about the 20MHz boards, 
 and we
> have received almost no feedback  on Ebay :( I hope that is a good  sign.
>
> Bye,
>  Said
>
>
>
>  _______________________________________________
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-- 

73,
Mike, N1JEZ
"A closed  mouth gathers no feet"

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