[time-nuts] FE-5680A Results so far

Orin Eman orin.eman at gmail.com
Thu Dec 29 12:55:48 EST 2011


On Wed, Dec 28, 2011 at 11:14 PM, mike cook <michael.cook at sfr.fr> wrote:

>
> 1) What is the expected 10MHz peak to peak voltage.  FEI doc seems to
> indicate 0,5V but I am getting only 200mv.
> 2) What is the sensitivity to 15V input level. I am only measuring 14,722
> (stable) on Pin1.
> 3) Could this low input voltage affect output voltage?
>
> The box locks after a couple of minutes but my TDS 210 is showing a very
> jittery  ( 9,98-10,02 MHz ) but well formed sine wave for 8 hours of being
> powered on.  Could this also be an artefact of low main power?
>


IME 9.98 to 10.02 is about as good as it gets measuring 10 MHz on the
TDS210.   I'd guess it's measuring the time between two zero crossings and
inverting it.  With a horizontal resolution of 1024 divisions, your +/-
0.02 MHz isn't surprising.  I got similar frequency measurements on my
TDS210 using a 10x probe, but got about 2V pk-pk voltage.

The fact you are a factor of 10 out is suspicious - check your probe!

Orin.



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