"Richard Hosking" wrote in message
u...

I am not very sophisticated mathematically and I have not studied
communication theory. Your article is most helpful. However it looks as
though it might be somewhat hard to implement in a small/slow codespace
such
as a microcontroller. (It may well be impossible to do this job in such a
device.)

In the August '98 QST, IK3OIL published an article on a CW decoder based on
a PIC16F84, which may well be, by today's standards, the most limited
microcontroller in use by hobbyists. (Well, I suppose you could tie one hand
behind your back by adding a Basic compiler on top of it or something like
that!) That particular device, while far from perfect, works a lot better
than the various PC based programs that I've tried.

Last I looked, he still had most of the information on his web site. I know
others have done work to improve on his program, but I don't know of any of
that work that has been published. One nasty feature is that a long series
of dahs can greatly confuse his algorithm and it can take a while to recover
from that. Were you to implement his algorithm in a '628 or something like
that, or even to simply replace the rather lengthy code he has around
displaying the speed with a little more work on the algorithm, I'm sure it
could be improved.

He did use an external decoder to recognize the CW signal, a 567 or
something of that ilk. Some folks have worked on that end, too. It seems
like there should be a better approach, but I haven't seen anything
dramatically better.

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