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

mike cook michael.cook at sfr.fr
Thu Dec 29 03:52:07 EST 2011

Le 29/12/2011 09:28, Chris Albertson a écrit :
> 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?
Loaded just by the scope input which I guess is 50ohm. probe is a 1x.
>> 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.
I'm going to rewire the breadboard. I have a Toshiba 3A 15V supply 
putting out 15,04. Must be leaking somewhere along the line. I'll see if 
I have something with a bit more to spare.
> 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.
I am looking at the right pin, measuring the voltage with TDS function.
> 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
> -- .
Probable. I tried T-ing to an independent counter and the wave form 
dropped near flat.

Thanks for your inputs guys

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