wrote in message
oups.com...
From: (Michael Black) on Sun, Jan 14 2007
12:24 am
This is precisely why two-tone oscillators are needed for testing
SSB transmitters. Because only then are you actually modulating
the output. Otherwise, it's just a carrier.
What happens at AF to RF translation in THIS group
is the emotional-baggage tie-in to the mythos of
morse such that direct RF on-off keying is somehow
a "pure way" to send "CW."
You may modulate the carrier with a tone but then it is not actually "CW"
anymore.
You may not think definitions are not important or consider those who wish
to adhere to important definitions to be carrying emotional baggage, but
definitions do have value and can be essential.
Remember the story of the 1800's era Indiana state legislure passing a law
to refine pie by rounding it off from 3.1415 to 3?
Those lost in the mythos
will contentiously state that audio tone generation
(with on-off keying of the audio) translated to RF
is "false" or "artificial."
Without on/off keying of the RF, it is simply is not "CW". I give you this;
you could call audio code that generates 2 RF states such as mark/space to
be "CW's" (continuous waveS). When the frequency or phase changes to a
different value from the original value, the "wave" ceases to be continuous.
However, you could conceive of the two RF states as being 2 continuous waves
that are either present or not, similar to 2 A1A transmissions (where one
continuous wave is present or not).
They are not equivalent. Not the same as A1A Morse. I do not consider belief
in fact to be emotional baggage.
Those folks just
haven't made the connection to spectral content of
ANY modulated signal...a few even contend that "CW"
(on-off keying) "has no sidebands" because "it is
just turned on or off!" :-)
Actually. I have never heard anybody say that. I have heard your
Canadian compatriot talk about transmitting "pure" sine waves which almost
imples no sidebands, when not considering on/off rise and fall times when
the RF is keyed (which he seems to ignore when he say says "pure sine
waves").
Perhaps worse is the group that believes
all-Class-C transmitters are "pure" in their
spectral content (as if those had no harmonics)!
Sigh... :-(
Again, most people who talk about "Class C" amplifiers are familiar with
their bias points being set above cut-off value for increased efficiency,
therefore they have distorted outputs and such people would know know that
they therefore generate lots of harmomics (and in some cases are intended
to, as in the case of frequency markers). Those who are not aware of this
do not tend not to speak about "Class C" amplifiers, specifically. They just
talk about their "linear AMPS" (which are hopefully biased at more like AB
than C :-))