[GPS_Standard] EFC voltage "cleanliness"

[Dimitri.p]

I also discoverd a a 0mv to 2.5mv to 23mv potential difference 
between different GND points.
So there is "something going on".
There is some investigating to be done, for sure.
I did use a 15k resistor and 0.1uF cap right at the oscillator EFC 
input that doesn't "seem" to make a difference.

Dimitri



At 11:19 PM 10/7/2015, Michal wrote:
>Hi Dimitri,
>
>What you have observed is most often a matter of (relatively) long 
>ground probe wire.
>To verify it you should just connect a hot point of a probe to your 
>ground and you will notice the same high level of (digital) noise.
>Use as short as possible contact between your ground and grounding 
>ring contact of a scope.
>Many demo boards are already equipped with two contacts for such 
>short contact and it really minimize this effect.
>
>You may also add some extra filtering on EFC pin with 100nF-1uF 
>capacitor just on the OCXO pins and 1k series resistor.
>
>Best 73,
>Michal
>sp2iqw
>
>
>W dniu 2015-10-07 o 23:00, Dimitri.p pisze:
>>Has anyone ever looked at their EFC output with a scope and if you 
>>have,  how "clean" is your EFC  ?
>>
>>I'm using the controller with a 10811-60111 oscillator and I seem 
>>to have a  200mV Pk-Pk jungle of signals when using wide bandwidth 
>>on my scope (150 MHz) that calm down to about 20-40mv when I limit 
>>the scope bandwidth to 20MHz .
>>
>>Either way it doesn't seem right so I wanted to compare notes.
>>
>>Thanks,
>>Dimitri
>>
>>
>>
>>
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