On Fri, 6 Nov 1998, John Payson wrote:

> |We could have several tables like this:
> |Length 1: E T
> |Length 2: A I M N
> |Length 3: D G K O R S U W
> |Length 4: B C F H J L P Q V X Y Z
> |Length 5: 0 1 2 3 4 5 6 7 8 9
>
> A simpler approach, if you use "1" for dash and "0" for dot is to
> add a single "1" before or after the received symbol and pad the
> rest with zeroes.  Thus:
>
> E : 00000010   .
> T : 00000011   _
> I : 00000100   ..
> A : 00000101   ._
> N : 00000110   _.
> M : 00000111   __
> S : 00001000   ...
> O : 00001111   ___
>
> etc.  This will allow most (all?) symbols and prosigns other than the
> standard distress call (...___...) to be handled with a single byte
> compare (the number of symbols of length LESS THAN eight, counting the
> null symbol, is equal to the number of symbols of length eight)

I did this *many* years ago with an EPROM-based wide path state machine
that latched the data back into the addresses.  Dit's and dah's
would be fed in as they occurred, which would drive the state
machine to a successively narrower solution, until the ASCII would
pop out the first 8 data bits.  A detected inter-character space
would reset the address latch and load the output data latch.

No CPU at all - worked great.  I don't recall how many EPROMS
it took to create the state machine...but it doesn't matter,
because I spent so much time building that thing so that
I could cheat on the morse code portion of my Ham license exam
that I didn't study and flunked the written part...

-Will