[time-nuts] Fw: AVAR calculation

[WarrenS]

Filip

I do not understand why filtering is not use more to see what is going on.
At the VERY least should display the moving averages for freq.
As I hope you can see on the XL plot attached, as compared to the other 
plots previously shown,
a good filtered signal shows more than JUST "a little slope" or a "may be 
significant" trend.
As you probable know ADEV is great for some types of short term noise, but 
not always so useful for longer term drift.
ADEV is not a good tool to give the results needed for this type of drift 
characterization. Low Tau Noise yes, Drift No.

BUT maybe the problem is:
The Plots shape Trend of that data SURE Looks to be phase and not Freq.
If the data is freq, Then that osc needs something, as it is showing an 
increase in ageing over time, maybe due to unplotted effects of temperature 
OR TBD.

ws

*****************
----- Original Message ----- 
From: "Tom Van Baak" <tvb at LeapSecond.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Sunday, January 10, 2010 3:27 PM
Subject: Re: [time-nuts] AVAR calculation
>
>> Comparing the overlapped Hadamard deviation and overlapped ADEV plots
>> indicates that linear frequency drift may be significant for tau >
>> 100sec or so.
>>
>> Bruce
>
> Agreed. The data set exhibits a drift rate of about -1.e-10.
> Attached is a raw frequency plot and you can just detect
> the slope in the wash of short-term noise.
>
> Also attached is a 100-second average frequency plot
> where the linear frequency drift is much more evident.
>
> /tvb
> ***************
> ----- Original Message ----- 
> From: "Filip Ozimek" <me_super at o2.pl>
> To: <time-nuts at febo.com>
> Sent: Sunday, January 10, 2010 1:20 PM
> Subject: [time-nuts] AVAR calculation
>
>>
>> I'm trying to calculate AVAR from collected data, but I would expect a 
>> different behavior of my DUT. Does anybody can
>> calculate the AVAR for me?
>> Gate time was 1s, without any deadtime between measurements,
>> this is a file http://www.fuw.edu.pl/~fozimek/pomiar61-frep.txt
>> with collected data.
>>
>> Thanks,
>>
>> Filip Ozimek
>>
> 
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