Terms such as "tightening up key shaping" and "soft keying" and "hard
keying" are neither used nor defined in the latest issue of the
Handbook. Worse, the latest handbook Figure 9.8 states that on-off
transitions of the RF envelope should follow a sine-wave curve, so I
don't quite know what to make of "DSP-generated raised-cosine key
shaping." As to Goodman and Garmmer, I wouldn't be able to identify
what is accurate and should be believed and what is inaccurate and
should be ignored, so I don't think I'll go looking for those
references. And no, Paul, I'm not trying to be a smart-ass here. I'm
just a simpleton trying to decode the language used by people who know
about such things.
Pointing me to the Handbook -- which I should have had sense enough
to do on my own -- did help in that it reminded me that key clicks and
bandwidth are the issues associated with rise times and curve shapes,
which is what I was really looking for, and Figure 9.9, if I study it
long enough, may point me to a decision as to whether or not I want to
modify ole #95. Either that, or wait for Al, VE1AWP, up the street
with his FT1000 to complain about my signal when we both try to contest
on the same band at the same time!
Great radio and lots of good people around to help us understand
it. Thanks, Paul.
Gary, VE1RGB
Paul Christensen wrote:
I would like to see someone please take this discussion one step
further and define the terms "hard" keying and "soft" keying, and
describe how either an operator or someone listening would be able to
discriminate between the two.
Gary, this topic has been covered in great detail in nearly every ARRL
Handbook for at least the last fifty years -- as well as other
publications. Some of the most relevant material is covered in
articles during the '40s and '50s by By Goodman and George Garmmer.
Not all of the material pertaining to "optimum key-shaping" is
accurate, but otherwise, the content is still accurate.
Many of us do not like to be held hostage to one rise/fall setting as
a "one size fits all" answer to our operating practices. With
DSP-generated raised-cosine key shaping, it's now possible to tighten
up key shaping at high CW speeds without appreciably consuming
additional bandwidth.
Paul, W9AC
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
