[time-nuts] Thought experiment on a low cost timing board

[Arnold Tibus]

> > My solution was to replace the 'HC390 change with the elegant
> > PIC-based divider chain invented by Tom van Baak. This uses the 10 MHz
> > signal as the PIC's clock, and the tight code based on a fixed number
> > of wait states makes a fully synchronous divider. I was unable to
> > measure ANY temperature effects. The PIC requires less real estate
> > than the 'HC390s and is also quite cost effective.
> 
> For those of you interested -- the free PIC source code
> for the divider is at:
> http://www.leapsecond.com/tools/PPSDIV.ASM 

Very interesting.
Thank you very much to both Toms for your work and the listing, and of
course to Brooks, who did a fantastic job.

> 
> Also I think Brooks Shera keeps a copy of the code at:
> http://www.rt66.com/~shera/index_fs.htm
> 
Unfortunately there is only the hex list of the pic code. 
As I would like to experiment as well with this modification 
and try to change some parameters to fit my LPRO 
and some different OCXOs I own, 
is there a way to get the commented source code of it? 

> Although written years ago for the PIC16C84 it works with
> little modification to almost any PIC. Remember to turn on
> the HS osc fuse, turn off the WDT fuse, and use a PIC part
> that handles a 10 MHz clock.
> 
> > ...
> > In short -- The Jupiter-T is a good timing receiver.
> > Hope these factoids helped -- Tom
> 
> Yes, thanks much. Always a pleasure to hear from you.
> 
The pleasure is as well mine to read all the good comments 
from you. 

I have still the idea to use a higher clock for the pulse 
counter instead of the 24 MHz for a better resolution.

I could not get any M12+ GPS-receiver on the market, 
so I bought the Jupiter-T as well and I want to compare the 
behaviour with the Trimble Resolution T later on, 
but before I have to get all that running.
(Is it possible to compete or beat the off the shelf 
solutions? ;-) ) 

Have always a good Time!

Arnold, DK2WT




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