[time-nuts] Phase microsteppers
wa1raj at arrl.net
Thu Mar 10 16:19:21 EST 2005
It's been quite some time since I've seen one of these units. Back a
decade ago I worked for the
company that makes LORAN-C solid state transmitters, and the Austron
were used in the timing racks (one for each redundant Cs standard). I
don't believe I've ever seen
one of these units "in the wild" at any place other than a LORAN facility.
I'd been considering building my own micro-stepper, but as a newcomer to
the T&F world I didn't
know if such a venture would be considered crude by today's standards.
Since I've not been able
to locate a commercial unit via any of the normal used and surplus
equipment channels, I'm entertaining
that design project once again. If some reasonable minimum step time was
all the resolution required
(10 nS, for instance) there's really not all that much to it -
especially with the silicon timed circuits that
are available for a dollar nowadays. The LORAN timers used lumped
constant delay lines and muxes
with counters to drive the tap selection for inserting LPAs (Local Phase
Adjustments), and a micro-
stepper could be built the same way.
I'd be really interested to hear what Tom has to say on the subject of
>Tom Van Baak wrote:
>>3) There's a lesson from the timing labs - they do
>>not typically adjust their C-fields at all. Instead they
>>adjust phase or frequency using *external* phase
>>micro-steppers or simply by *post-processing* the
>>raw phase data from their counters.
>Tom, thanks for the always helpful information. I may come back on to ask some further questions about your other points (although they are pretty self-explanatory) but wanted to follow up on this point.
>I've known about microsteppers for a while, but I've never seen one on
>eBay or anywhere else that I hang out. Are they possible to find
>without special connections in the T&F field? What brands/models are
>good to look for? Sounds like a very interesting gadget to play with,
>if I could find one.
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