[time-nuts] looking for data on time code display

Morris Odell vilgotch at bigpond.net.au
Sun Dec 11 22:45:06 EST 2011


> I had hoped the frequencies listed on the controls might trigger some
association in someone who's knowledgable about time-codes. 250 Hz 

> doesn't seem to be a legal IRIG time-code frequency, although 1 kHz is.

I'd try feeding it with various frequencies as others have suggested and see
what happens. It's unlikely to have been used with other time codes such as
SMPTE.

I have an earlier unit made by Datachron, now defunct, which looks
superficially similar but uses DTL logic. Mine is definitely an IRIG decoder
and the funny filter frequencies may have been meant for manually shuttling
tapes at non standard speeds. After a lot of messing around (a story in
itself)  I have resurrected mine and use it as a nixie clock, fed with IRIG
B generated by a modern micro from the output of a GPS receiver. There's
more logic in the $9 AVR chip than the whole IRIG decoder which would have
cost thousands when it was new!

And while I'm on the subject, anyone got any DTL JK flip flops to spare to
keep the old box going? I've had to replace quite a few chips which probably
died when the device was fed with higher than specified mains voltage in its
early life.  The +5V supply was unregulated :-(

Morris VK3DOC
Melbourne, Australia






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