[time-nuts] Enhancing the TIC232 code for better data

Richard H McCorkle mccorkle at ptialaska.net
Sun Aug 13 18:25:06 EDT 2006


I am indeed using a TVB style divider for my DUT 1PPS
and since it has a square wave 1Hz output, I programmed
an inverted 1Hz output for my TIC test box DUT 1Hz.
That way any drift over time keeps the phase detector and
TIC well away from the zero crossing during long-term testing.
I remove the offset in post processing and use the corrected
data for analysis.

----- Original Message ----- 
From: "Brooke Clarke" <brooke at pacific.net>
To: <billj at ieee.org>; "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Sunday, August 13, 2006 9:16 AM
Subject: Re: [time-nuts] Enhancing the TIC232 code for better data


> Hi Bill & Didier:
>
> I think that Richard is using the tvb divider on his 10 MHz reference to
> get to 1 PPS and that has a square wave output.
>
> Have Fun,
>
> Brooke Clarke
>
> -- 
> w/Java http://www.PRC68.com
> w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
> http://www.precisionclock.com
>
>
>
> Bill Janssen wrote:
>
> >Didier Juges wrote:
> >
> >
> >
> >>Second thoughts about inverting the UTC 1PPS. I have read in a previous
> >>post that for most GPS receivers, only the leading edge of the 1PPS
> >>pulse is tightly controlled (and intended to be synchronous with the
> >>satellite signal), the falling edge is not. If this is true, we want to
> >>make sure we keep that edge the way it is and then invert the 1PPS from
> >>the DUT, if this is possible.
> >>
> >>Also, at least with my Jupiter receiver, the 1PPS is a fairly short
> >>pulse, not nearly 50% duty cycle, so inverting it might not give much
> >>improvement.
> >>
> >>Any thoughts?
> >>
> >>Didier
> >>
> >>
> >>
> >Would it be feasible to clock a flip-flop with the pulse ? that would
> >give a 50% duty
> >cycle but with one  pulse per two seconds. I hate to slow the signal but
> >it might be feasible.
> >
> >Bill K7NOM
> >
> >
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