[Test-Equipment] Frequency accuracy

Tue, 24 Sep 2002 19:46:06 -0400

In your initial post you mentioned the ionosphere, not the oscillators. It
is all a function of the desired accuracy, but we were mostly discussing
disciplined oscillators. Therefore, I still feel, that the statistics
required is that for the measurement equipment. Additionally, of course,
then according to you, the source, to be measured, would suffer the way. So,
if we have a source that is not stable as a function of time, and
measurement equipment suffering the same problem, it is a hopeless
situation. BTW, I believe  I have a way to get the signal frequency to be
measured, locked, and looked at with an FFT analyzer. Regards - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ, 07731
(732) 901-9193

----- Original Message -----
From: "Francesco Ledda" <[email protected]>
To: "Mike Feher" <[email protected]>; <[email protected]>;
<[email protected]>
Sent: Tuesday, September 24, 2002 6:54 PM
Subject: RE: [Test-Equipment] Frequency accuracy

> No, I was referring to oscillators in general.  Since oscillators drift in
> time, the estimate of the mean is meanness.  This means that increasing
the
> observation time does not improve the accuracy of the mean estimate.
>
> Regards, Francesco
>
>
>
>
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of Mike Feher
> Sent: Tuesday, September 24, 2002 4:40 PM
> To: [email protected]; [email protected]
> Subject: Re: [Test-Equipment] Frequency accuracy
>
>
>
> Remember, back then we had to use counters that took a long time for a
> single measurement, especially of the precision that you are talking
about.
> There were no such things as reciprocal frequency counters at the time.
> Additionally, as I recall, the 60 KHz transmissions were modulated with
> embedded time and other data, and is, like now, far from a steady carrier.
I
> have had several private emails with other contributors to this thread, at
> their choice, and actually wish the whole group could have benefited or
> contributed to them. This reflector is not a real busy one, so this
> discussion, at least to me, has been really interesting. This is a neat
> topic, and I hope the thread continues. Francesco earlier mentioned that
the
> statistics associated with the measurement cannot necessarily be
considered
> Stochastic, or time invariant. Of course he was referring to the
atmospheric
> phenomenon. At the time, my argument for a statistical measurement was due
> mainly to test equipment variances as a function of time. I am still
willing
> to listen and learn, as this is a fascinating phenomenon for me. Regards -
> Mike
>
>
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell NJ, 07731
> (732) 901-9193
>
>
> ----- Original Message -----
> From: <[email protected]>
> To: <[email protected]>
> Sent: Tuesday, September 24, 2002 5:09 PM
> Subject: [Test-Equipment] Frequency accuracy
>
>
> > I wonder if any of you have ever received the 60KHz from WWVB and
plotted
> > it against WWV at 5 ,10, or 15MHz. It should give you a new idea of
> > propagation errors and frequency comparison accuracies. Do you remember
> how
> > we used to plot a comparison with WWVB and the House Standard and hope
> that
> > we were accurate to 10 to the -10th?????
> > n5mqa
> >
> >
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