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

[Chris Albertson]

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

> Hi,
> Just got my cheapo 5680A.  It was accompanied by a little teddy bear
> clutching a L7805CV !
>
> Got a couple of questions.
>
> 1) What is the expected 10MHz peak to peak voltage.  FEI doc seems to
> indicate 0,5V but I am getting only 200mv.
>

I'm getting a lot more, about 2V peak to peak.  What are you loading it
with, I'm using a 10X scope probe.   How are you measuring the voltage?


> 2) What is the sensitivity to 15V input level. I am only measuring 14,722
> (stable) on Pin1.
>

The voltage in pin 1 is up to you.  The spec says you need to supply
anything in the range of 15V to 18V.  I've been using about  16V from a
variable bench type power supply.

3) Could this low input voltage affect output voltage?
>

I was thinking the same thing.   I you sure you are looking at the correct
pin?   I noticed a very low signal on pin-6.

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?
>

Could be your counter has trouble with low amplitude sine wave.  Or it is
loading the signal.  My HP counter has trouble with mV level signals too.
But I found my scope has a vertical amp output.  Makes the scope work like
an RF amp
-- .


Chris Albertson
Redondo Beach, California