On Wed, 25 Feb 2015, Stephen Thomas Cole wrote:

Michael Black wrote:
On Tue, 24 Feb 2015, gareth wrote:

What is the point of digital voice when there are already AM, SSB
and FM for those who want to appear indistinguishable from CBers?

Perhaps it is cynicism from the manufacturers who introduce such things
as they see their traditional highly-priced corner of the market
being wiped away by SDR technologies?

Because it's something new, at least to amateur radio.

The phasing method of sideband was common in the early days of amateur
SSB (I recall reading the first rigs were filter type, but with really
low IFs, then phasing, then crystal and mechanical filters took over from
phasing). It offered up a lot on transmit and receive, though not perfection.

But now phasing is used a lot, because digital circuitry has made it
viable. I remember seeing some of the potential when phasing was still
analog, but I also remember reading articles where it was clear others
didn't see the potential. Sometimes ideas become lost when something becomes commonplace.

Who knows what would come from digital voice. But I remember 30 years
ago one local ham being interested in it, not to the extent of putting
something on the air, but as information from the computer world started
flowing in, the potential started being there. YOu can't resist new
things and say "they have no use", you have to embrace the new and see
what can be done with it. Maybe not as initially seen, but maybe it fits
in somewhere else.

Amateur radio has never done much with envelope elimination and
restoration (was that what it was called? I now forget). It's in one of
the sideband books, and Karl Meinzer of AMSAT fame wrote about it in QST
about 1970. Break the SSB signal into two components, so you can
multiply it up to a higher frequency, then modulate the output stage. If
you have an efficient modulator, you can do away with linear amplifiers
(which is why it was in that SSB book). I gather he used the scheme in
at least one of the amateur satellites after Oscar 6.

But what happens in the digital age? Can you generate the two streems,
in essence but not so simple an FM component and an AM component, without
needing to generate SSB and then extract the two streams? I don't know,
but so much digital processing is being done now, it may be something to
look into. With solid state devices and class D amplifiers, modulating
high level class C amplifiers can't be as much trouble as in the old
days. Maybe it amounts to nothing, but maybe it overall becomes more
efficient, if it can be done.

Maybe there's no value to digital voice, except that in the process of
learnign about it, and implementing it, one can learn something. Maybe
something merely new to the person learning, but maybe something
completely new. No advances are made without learning, the learning triggers new advances.

Michael

You do realise that you're responding to a troll post, right?

Only because you continue to keep that war going even as it spills out of
the UK newsgroup.

I didnt' "feed the troll", you do that all the time by keeping up the
vendetta. I chose to say something about the topic, certainly about how
ideas advance, and it exists whether or not he is a troll.

Michael