[time-nuts] new GPSDO kit

[SAIDJACK at aol.com]

Hello Brooke,
 
>>Can  you say more about what this means?
>>"It  generates a low-noise 10MHz signal with typically better than
>>1E-010 precision and accuracy (0.1ppb) on average"

let me explain. I took some measurements over night, see attached files.  
This was done with the unit shielded from airflow and sitting on a bench, and 
 the time constant increased by a bit to account for the benign no-airflow  
environment.
 
You can see that the ADEV at any time from 1s to 10,000s averages and  
beyond is about 1.3E-010 worst case. So you can assume that the  average 
accuracy (because of GPS being the absolute reference) and relative  precision (the 
ADEV around the average value) is about 1.xE-010 on a  typical unit.
 
Also note that the second plot shows a standard deviation of the TI  
interval of 13.3ns which is significantly better than the 25ns spec.
 
Lastly, the performance of 3E-012 at 10,000s is almost 3x better than  spec.
 
This was a random unit I grabbed that had been sitting on a shelf for some  
months, and I only let it run for ~15 minutes after power-on before I  
started the measurement.
 
This is one of the beautiful features of the TCXO we use: it does not  
require long retrace and warmup periods. It runs pretty much right out of the  
box, even after months in storage. An OCXO based unit probably would have  
required 8+ hours to stabilize from its retrace after such a long  off-period. 
In fact this unit ran at only about 1.5ppb error before disciplining  
started, meaning the TCXO and our firmware kept that frequency accuracy over  
several months on the shelf without power.
 
So you could go to a work-site, set up the unit and wait about 15 minutes,  
then get a really clean, accurate, and stable reference signal.
 
Hope that makes sense,
Said
 
 
 
 
In a message dated 4/4/2014 16:40:45 Pacific Daylight Time,  
brooke at pacific.net writes:

Hi  Said:

Can  you say more about what this means?
"It generates a  low-noise 10MHz signal with typically better than 1E-010 
precision and  accuracy (0.1ppb) on average"

Have Fun,

Brooke  Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html

SAIDJACK at aol.com  wrote:
> Hello everyone,
>   
> sorry for the  plug, but we just announced a new $568 complete GPSDO
> reference  kit.
>   
> This unit is a tiny desktop unit with 10m  antenna, power supply, cables,
> CD, and other accessories. It is a low  cost addition to our Fury GPSDO  
line,
> and contains a really good  TCXO, a uBlox GPS receiver, and various power
> options. I believe this  is the lowest-cost real GPSDO in mass production
> available on the  market right now, and being a true GPSDO it has  some 
fairly
> good  phase noise and stability specs.
>   
>  
http://www.jackson-labs.com/assets/uploads/main/LC-XO-Plus_PressRelease.pdf
>    
> bye,
> Said
>  _______________________________________________
> time-nuts mailing list  -- time-nuts at febo.com
> To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the  instructions  there.
>

_______________________________________________
time-nuts  mailing list -- time-nuts at febo.com
To unsubscribe, go to  
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the  instructions there.

-------------- next part --------------
A non-text attachment was scrubbed...
Name: LC-XO-Plus.zip
Type: application/zip
Size: 56870 bytes
Desc: not available
URL: <http://www.febo.com/pipermail/time-nuts/attachments/20140405/b20ebb1a/attachment-0001.zip>