[time-nuts] GPSDO simulation tool

Chris Albertson albertson.chris at gmail.com
Sat Mar 22 16:37:36 EDT 2014

Not complaining.  Just looking for open source tools to do the
analysis before I write them myself.  I figured someone must have done
this.  Found it in ../tools as you said.  Thanks.
Plotting is the easy part, any number of tools to do that, analysis is harder.

I'm looking at your simulation software, thinking I could add a PID
autotunner.    Even using brute force search it could finish over
night.  Compared to the months it would take using real hardware.

On Sat, Mar 22, 2014 at 1:00 PM, Tom Van Baak <tvb at leapsecond.com> wrote:
> 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.
> /tvb
> ----- 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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Chris Albertson
Redondo Beach, California

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