[time-nuts] Method for comparing oscillators

[WarrenS]

Ulrich

Thanks, I stand corrected, Your point was right on. 
My point was; Just maybe John did not really want all the Allan stuff, I could not tell.
AND true, sorry I did miss YOUR point. 
It would seem that you where the ONLY one of us that was NOT confused by the words.

warren

****************** 

----- Original Message ----- 
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
To: "'Discussion of precise time and frequency measurement'" <time-nuts at febo.com>
Sent: Monday, August 03, 2009 11:47 PM
Subject: Re: [time-nuts] Method for comparing oscillators


Warren and John,

my point has not been to judge who has to be interested in what. My point
has only been to use the right terms for it. Let me give an example: John
uses the term

> ...but I am more concerned with ... and stability over time

Well, stability over time is what exacly is displayed in a tau-sigma-diagram
of an oscillator. Since only a few words before he is saying that he is NOT
intersted into Allan Deviation plots, then he is perhaps interested into
something else? 

Best regards
Ulrich Bangert

> -----Ursprungliche Nachricht-----
> Von: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] Im Auftrag von John Green
> Gesendet: Montag, 3. August 2009 21:36
> An: time-nuts at febo.com
> Betreff: Re: [time-nuts] Method for comparing oscillators
> 
> 
> Part of using this method is that, at some point, the DUT 
> must be set to the same frequency as the reference. (As close 
> as I can get it anyway.) So, accuracy and stability are 
> addressed separately. For TCXOs, set to frequency and watch 
> the drift over time. I have an environmental chamber so I can 
> do freq vs temp testing. This is actually better done with a 
> good frequency counter using the Tbolt as reference. The 
> problem with OCXOs is that when you adjust frequency, you 
> have to wait a long time for the thing to settle in. That is 
> why I will set up and go about my daily duties, only checking in
> periodically. I mainly want to look at 2 things. Short term   
> stability, by
> this I mean from turn on to maybe an hour. When used in 
> communication equipment, how fast an oscillator gets to 
> within tolerance as well as retrace are important. Next is 
> long term. Hours to weeks and even months. I would like to be 
> able to do years, but at some point I have to be realistic. 
> Yes, Allan deviation plots are interesting but I am more 
> concerned with ordinary spectral purity and stability over 
> time and perhaps temperature that will have practical effects 
> on either test equipment measurements or communication system 
> performance. This is interesting conversation, by the way. 
> Thanks _______________________________________________
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