On Tue, 8 Jul 2008 06:55:04 -0700, Tom Van Baak wrote:
[...]
Yes, it's quite flexible and you can have a lot of fun replacing
the OCXO. I'm assuming a number of you will be trying this
in the coming months.
But even with the onboard OCXO, it allows you to change the
time constant which can make a
I am calculating plotting the ADEVs (or OADEVs) of the Thunderbolt's own PPS
and OSC error estimates. The values are its estimate in the error of the PPS
signal edge/OSC zero crossing to GPS time. I have queue of 22000 entries that
tracks the last 22000 values of PPS and OSC errors. Every
Yeah, it's kinda flakey to rely on the device to compare
its output signals to its own interpretation of GPS time,
but it's free and requires no external equipment.
Just because something is free doesn't mean it has any
meaning. Stop and think about what your statistics are
showing.
The
I do modify the OSC ppb value to morph it into nanoseconds of error before I
feed it to the ADEV code (at least I think I do... the documentation is not
really clear on what the value really is).
The constant 1 second offset that I added to the data makes absolutely no
difference in the
As far as what the statistics are showing... well they show
the ADEV values of the Thunderbolt's own measurements
of the signal errors (auto ADEV?). How those compare to
measurements against an external reference is left as an
exercise to the reader.
What you're calculating is the
The manual doesn't give much direction on tweaking the disciplining parameters.
Also, not having anything better to compare results to, I'm pretty
handicapped. Has anybody done any tweaking and perhaps can offer any
suggestions?
Over the weekend I was able to get a GPS antenna on the roof
Tom Clifton wrote:
The manual doesn't give much direction on tweaking the disciplining
parameters. Also, not having anything better to compare results to, I'm
pretty handicapped. Has anybody done any tweaking and perhaps can offer any
suggestions?
Over the weekend I was able to get a
The Thunderbolt attempts to align the specified PPS and OSC edges with the GPS
satellite time signal. The PPB parameter is its estimate of the error of the
oscillator edge from where it needs to be. They specify it in mysterious
parts-per-billion, but never really say billions of what.
@febo.com
Subject: Re: [time-nuts] Thunderbolt Loop Damping
Tom Clifton wrote:
The manual doesn't give much direction on tweaking the disciplining
parameters. Also, not having anything better to compare results to, I'm
pretty handicapped. Has anybody done any tweaking and perhaps can offer any
