[time-nuts] [Fwd: Re: Simulating LORAN-A GRI Timing Generator]

[paul swed]

Well I might be crazy but this seems perhaps easy since reading the link
provided.
The slaves listened to the master and provided a pulse.
So for at least a rate 1 chip could do the job. Essentially the master pulse
and then a delay to the slave position.
If I am interpreting the info correct the pulse were 40 us wide and made of
the carrier frequency like 1.95 MC.
A solution would need 2 or 3 of these widgets to give the 3 lines. But do
not need to be synchronized because the value of the informations contained
within the delay relationship between the master and slave.
Regards
Paul

On Sat, Jan 8, 2011 at 10:08 AM, J. Forster <jfor at quik.com> wrote:

> Pondering some more on this, doing some calculations (spread-sheets) the
> actual scheme emerge... the range of 0 to 7 is not selected by accident.
>
> The base pulse repetition rate is 30 ms, 40 ms and 50 ms. The pulse
> repetition rate modifiers modifies the repetition rate by -100 us per
> step. It would only take two (or possibly three) wheels to select PRR.
> This explains the high rate starts with 33 3/9... it also makes the
> receiver design easier to understand.
>
> Very interesting observation! I did the calculation using Excel (attached)
> but missed the 100 uS increments., I was blinded by modern precision.
>
> Since the LORAN Indicator has sync circuits, your observation is a nice
> simplification. Thank you.
>
> So a 10 kHz source would suffice for PRR settings. A phantastron divider
> from a 100 kHz standard should do it in those days technology, if not a
> 10 kHz standard was used directly.
>
> Only the delayed pulse would need the full set of thumb-wheels.
>
> Cheers,
> Magnus
>
>
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