[GreenKeys] Different Type Of TU

[JC White]

A couple of months ago I came across an article for constructing a TU that uses no tone filters at all.  The Dec 1991 issue of ELEKTOR, page 18 - 20, has an FSK decoder based on a pair of one-shots.  Basically, they are set to react to the period of an incoming tone, so actual shift is not very important.  Neither are the actual tones, as long as the periods of the one-shots are adjusted (somewhat).  Having tossed together the circuit I am rather surprised how well it works.  When I have more time I will play with the circuit more and see how it compares to my other TUs (ST-6, Dovetron, NS-1, several others).
By the way, do any list members recall mountain California TTY guy Grand Storey, who sold tone filters for many years?  Turns out I have an ancient TU with his filters it.  Doggone things works rather well!

JohnWB6BLV
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