[time-nuts] Chinese GPSDO 10 MHz error

Bob Camp kb8tq at n1k.org
Wed Aug 26 17:55:38 EDT 2015


Hi

Further investigation by list members in China came back with the information that this particular 
design is indeed a FLL. The error is considered “acceptable” by the designer. This is not the case
on the various CDMA oriented GPSDO’s we typically play with in the US and Europe. All of those 
designs (as far as I have seen) use PLL’s as their final lock stage. 

Bob

> On Aug 26, 2015, at 3:18 PM, Perry Sandeen via time-nuts <time-nuts at febo.com> wrote:
> 
> Hi,
> 
> 
>  
> On the EEVBLOG  (http://www.eevblog.com/forum/index.php)
> 
> 
>  
> They mention that the "2014-11-06"version GPSDO that was “most extensively tested, so far (by ke5x and others).
> 
> 
>  
> (Has a) known bug, outputfrequency is not exactly 10mhz (9,999,999.999,800 Hz). This translates to ~2hzerror at 100ghz.”
> 
> 
>  
> A question is if this bug isjust for this particular model or all other versions suspect?
> 
> 
>  
> I realize that in and of itsself it is very small error, but errors tend to multiply or cause incorrectconclusions to testing.
> 
> 
>  
> Another question is will the LHdisplay unit they offer work with other Trimble units such as are offered byRDR?
> 
> 
>  
> That said, these models seem tobe a very nice turn-key systems.
> 
> 
>  
> Regards,
> 
> 
>  
> Perrier
> 
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