On May 5, 2008, at 1:35 AM, G4ILO wrote:
Mike Scott-7 wrote:
I am surprised to hear that people don't like the extra bandwidth
in the
audio response in the K3.
Because people use their radios in different ways. Some of us don't
want to
waste energy generating frequencies that add nothing to the ability
to be
heard when signals are weak. We don't use SSB to have "armchair
copy" chats
using hi-fi speakers.
Nobody is asking that improved low frequency response should be
taken away,
just that it should be made an option. I'm not sure that the range of
adjustment provided by TX EQ is great enough to restore the audio to
the way
it was before.
I feel lots of heat but very little light on this subject here. There
really is no problem. A SSB transmitter is just a linear translator
that moves your baseband signal (audio in this case) up into the RF
spectrum where you want it. When you mix to translate the signal
somehow you need to get rid of the image. That means either filtering
it out (filter-type SSB generator) or cancel it out (I/Q type SSB
generator). Regardless, it doesn't matter whether you provide the
bandwidth shaping at baseband or after your first mixer. DSP at
baseband, DSP at the first IF, or a crystal filter at first IF or
second IF doesn't matter. Any will solve the problem for you.
I think Elecraft has already thought this out.
Next we will talk about how it is ALL digital, that there is no such
thing as analog. ;-)
Claude Shannon for President.
Brian Lloyd
Granite Bay Montessori School 9330 Sierra College Bl
brian AT gbmontessori DOT com Roseville, CA 95661
+1.916.367.2131 (voice) +1.791.912.8170 (fax)
PGP key ID: 12095C52A32A1B6C
PGP key fingerprint: 3B1D BA11 4913 3254 B6E0 CC09 1209 5C52 A32A 1B6C
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