[time-nuts] GPSDO simulation tool

Tom Van Baak tvb at LeapSecond.com
Sat Mar 22 16:00:09 EDT 2014

Hi Chris,

I'm pretty sure John distributes complete source code to TimeLab as part of the installation.
My source code is at www.leapsecond.com/tools
There are also many open source plotting tools available.
Not sure what you're complaining about, really.

Please try using the GPSDO simulator and let's talk time & frequency instead of open & closed operating systems.

Here's an example of what you can do -- varying the pre-filter from 1 to 1000 seconds.
First, using the cute little Adafruit "Ultimate GPS" MTK3339 board: gpsim-22.gif
Second, using the fancy CNS-II M12+T box: gpsim-23.gif
Both with the same OCXO and same gpsim1 default P,I,D parameters.

These plots would have taken weeks of data collection. Instead it took 20 seconds with the simulator.


----- Original Message ----- 
From: "Chris Albertson" <albertson.chris at gmail.com>
To: "Tom Van Baak" <tvb at leapsecond.com>; "Discussion of precise time and frequency measurement" <time-nuts at febo.com>
Sent: Saturday, March 22, 2014 11:56 AM
Subject: Re: [time-nuts] GPSDO simulation tool

Yes I could run most any MS Windows software on my iMac.   But running
it is not the point.  Closed source software like this is just a
"magic black box" and you can't see how it works.

The point is like this:  Why build a GPSDO when you can simply buy a
Thunderbolt, apply power and go?    The same answers apply to
software. You want to learn the issues involved, you want to modify it
or use it in a different environment.

Especially the last part, different environment.  I'd like to have my
GPSDO draw performance plots and some diagnostics on a little cell
phone size LCD screen.

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