[time-nuts] Measuring gpsdo vs itself

[WB6BNQ]

Hi Tom,

I think you missed the point.  He is trying to measure the noise floor of the counter itself.  So what he wants to know is if using the same signal for the time base and input, would that cancel out the signals contribution to the noise measurement.

Bill....WB6BNQ

Tom Van Baak wrote:

> Bill,
>
> This is usually a good idea, since the counter then has both a good short- and long-term stable/accurate timebase, inherited from the GPSDO. It means the internal timebase of the counter is no longer a factor in measurement stability or accuracy. There are exceptions to this, but I'll guess your setup is not one of them. This configuration is especially good for 1PPS TI measurements since it means a short 100 ns TI measurement is just as accurate as a long 0.999999900 s measurement.
>
> I'm not sure I'd call this a "reference independent" system; it's simply using a GPSDO as the reference instead of the internal XO timebase of the counter.
>
> /tvb
>
> ----- Original Message -----
> From: "Bill Dailey" <docdailey at gmail.com>
> To: "Time Nuts" <time-nuts at febo.com>
> Sent: Sunday, November 04, 2012 7:19 PM
> Subject: [time-nuts] Measuring gpsdo vs itself
>
> > If I use a gpsdo as my reference and feed the same 10MHz into a counter does that yield the reference independent noise floor of the measuring system? Seems to me it would look like an ideal reference with respect to the measuring system.  Thanks,
> >
> > Doc
> > KX0O
>
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