Hello time-nuts community,
thanks to your feedback and that of others, I could make additional
progress on my journey to understand powerlaw noise :)
I would like to reiterate what I have learned so far. Please comment on
anything that you think is done wrong.
Hello Magnus,
I'm sorry, but I can't follow you here.
I know that time deviation values and fractional frequency values are
related via integration, so I think I understand the third line.
But I don't know what is meant especially with the first one:
What is d(t)?
What is D? Is this the
Wolfgang,
Remember to scale the double-integral right:
d(t) = D
y(t) = integrate(d(t),t) = y_0 + Dt
x(t) = integrate(y(t),t) = x_0 + y_0*t + D/2*t^2
Did you miss the 1/2 factor somewhere?
That would make sense for the Random Walk phase noise.
Cheers,
Magnus
On 03/09/2015 04:57 PM, Wolfgang
Hello Tom, hello time-nuts,
Have a look at the 20 plots in:
http://leapsecond.com/pages/allan/Exploring_Allan_Deviation_v2.pdf
Thanks for sharing the data and the PDF! It's good to have reference values.
I also had a look at the stable32 user manual [1] to see how it
calculates the PSD
On 03/06/2015 10:29 PM, Magnus Danielson wrote:
I have checked several sources, and they match up with the IEEE 1139 in
this regard.
I have also evaluated the equation for Allan variance for the random
walk noise, and it matches up with the references and what I put here:
. The raw data is at:
http://leapsecond.com/pages/allan/
/tvb
- Original Message -
From: Wolfgang Wallner wolfgang-wall...@gmx.at
To: time-nuts@febo.com
Sent: Monday, March 09, 2015 8:57 AM
Subject: Re: [time-nuts] AVAR - S_Y conversion
On 03/06/2015 10:29 PM, Magnus Danielson wrote
Wolfgang,
I have checked several sources, and they match up with the IEEE 1139 in
this regard.
I have also evaluated the equation for Allan variance for the random
walk noise, and it matches up with the references and what I put here:
On 03/05/2015 07:23 PM, Attila Kinali wrote:
Servus!
Servus :)
On Thu, 05 Mar 2015 14:35:51 +0100
Wolfgang Wallner wolfgang-wall...@gmx.at wrote:
For the random walk noise the expected line is off by a factor of
exactly 2 from the calculated plot, and I don't know how to explain this
Servus!
On Thu, 05 Mar 2015 14:35:51 +0100
Wolfgang Wallner wolfgang-wall...@gmx.at wrote:
For the random walk noise the expected line is off by a factor of
exactly 2 from the calculated plot, and I don't know how to explain this
behavior.
I'm probably the wrong one to answer, as I have
Hello time-nuts community,
I hope this is the right place for the following question :)
I'm dealing with the simulation of powerlaw noise, and I stumbled upon
something I cannot explain when I tried out some formulas of IEEE 1139 [1]:
According to Table B.2 in [1] the one-sided power spectral
Hi
The use of femtoseconds come from the AVAR it's self. It was originally defined
by time domain people. It's delineated by a Tau dimensioned in seconds. The
time domain noise that's 1x10^-12 or 1x10^-15 down at one second does indeed
have units of 1x10^-12 or 1x10^-15 seconds.
As with any
To: Discussion of precise time and frequency measurement
Sent: Sunday, June 20, 2010 11:32 AM
Subject: Re: [time-nuts] AVAR Femtoseconds
Hi
The use of femtoseconds come from the AVAR it's self. It was originally
defined by time domain people. It's delineated by a Tau dimensioned in
seconds
Hi,
I'm trying to compare a various methods of time and frequency
comparision: GPS common-view, GPS carrier-phase and GPS TWSTT. Does
anyone know what is the floor level for these methods in AVAR?
Filip.
___
time-nuts mailing list --
Robert Benward wrote:
Bob
Boy, you guys are really making me read a lot. I'm digesting Wiki right
now.
I see tau, but does identifying a tau of 1E-14 allow you to say you are
locked to 10fs? The smallest tau I've seen in my E1938 collection is 1E-1.
Bob
tau is the time over which the
On 06/20/2010 11:53 PM, jimlux wrote:
Robert Benward wrote:
Bob
Boy, you guys are really making me read a lot. I'm digesting Wiki
right now.
I see tau, but does identifying a tau of 1E-14 allow you to say you
are locked to 10fs? The smallest tau I've seen in my E1938 collection
is 1E-1.
Bob
Hi
While the units are more properly femto seconds/ second you do indeed see 1s
AVAR plots labeled in fS.
Bob
On Jun 20, 2010, at 6:25 PM, Magnus Danielson wrote:
On 06/20/2010 11:53 PM, jimlux wrote:
Robert Benward wrote:
Bob
Boy, you guys are really making me read a lot. I'm digesting
Second thought, look at the tau=1 to 10 s and you see that it first
rises before the usual slope. This is the effect of averaging in the
counter. I would suspect that a HP53132A is being used.
Magnus,
You're correct about averaging effects; for example, see:
Tom Van Baak pisze:
Hi Filip,
See attached. Let me know how your results differ from this.
It looks like 1.75 hours of frequency data of a 250 MHz DUT.
You first convert your raw frequency measurement data into
normalized frequency error data (i.e., subtract and divide by
f0 = ~250 009 770
That data represents a beat note between two optical frequencies: Nd:YAG
laser stabilized to hyperfine transitions of molecular iodine and
optical frequency comb that is phase locked to the SRS FS-725 rubidium
standard. And it seems that AVAR of this measurement is lower than
values for
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.
Filip Ozimek wrote:
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
-
From: Filip Ozimek me_su...@o2.pl
To: time-nuts@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
Filip Ozimek wrote:
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
: Re: [time-nuts] AVAR calculation
Ulrich's PLOTTER application is a good tool for that; mine doesn't support
frequency input yet. If you haven't tried PLOTTER, it's the second download
on the page at http://ulrich-bangert.de/html/downloads.html . Be sure to
select Data is frequency from the Time
-boun...@febo.com]on
Behalf Of Tom Van Baak
Sent: Sunday, January 10, 2010 3:09 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] AVAR calculation
John,
You can convert frequency to phase (time interval)
using fr2ti under www.leapsecond.com/tools/
/tvb
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