robert bristow-johnson wrote:
On 6/9/15 4:32 AM, Vadim Zavalishin wrote:
Creating a new thread, to avoid completely hijacking Theo's thread.
it's a good idea.
I agree that there was the possibility of an unstable offense
resolution, but I wasn't aware people were being afraid of that concept.
Look, it's a matter of decent engineer interactions and more so: decent
scientific ausbildung, scientific method, and let's say "respect after
failure". Moreover, for a lot of people who either are glad not to have
to delve much in the mathematics, or who didn't get the chance to access
proper higher education in the various fields, it might be the
intellectual robbery that could be imminent isn't clear, and certainly
disgusting.
I was glad to have been informed, as undergrad student, of the
underpinnings I've put forward here, and maintain there are a few main
things about sampling that I think some people ought to know, and as it
so happens do know a bit about now. It's decent for academic engineers
to follow a path where first they score enough points in the undergrad
realm, then get taught decent mutual respect and communication modes
about engineering subjects, then hopefully learn how to master a subject
in science, and then they're off to be a decent, usually on the cool
side, person with the ability to get into engineer problems at the
appropriate level and deal with scientific sides to their work.
I've been around a European (at that time) top university long enough to
know why that is so, and what's wrong with all kinds of funny and
slightly interesting nerdy students trying to work themselves to a
position of power, and I won't condone it in general, if I can in all
decency help it. So when people work on a subject, get corrected at
undergrad level (the same where many have passed through and are
satisfied and usually successful with, and where the subjects taught are
centuries old and tried) it's not proper to just happily go on and act
as if a personal and professional sense of honor can be seconded to some
end that will justify all inter-engineer injustice, and in the end
social interactions with all people matter not enough to be a solid and
recognizable person.
Anyhow, as a summary once more: the only proper way to sample a signal
(with the obvious conditions luckily reiterated regularly) and process
it or play it back properly is based on a theory that cannot be
internally reversed or made into a local signal processing idea, while
maintaining general applicability. And I know there are some signal
precautions and some modes of processing possible that IMO have been
thought about at least in the 60s, and maybe before I was born.
Unfortunately a lot of software and DSP code is just as limited as it is
and that's not going to change if enthusiastic and clearly extremely
immature mathematicians are going to try out new "theories" or engage in
opportunistic word games. It just is no different, even if I'd want it
to be.
So once more: it doesn't matter what you do in sample space much, if I
don't see sinc function reconstruction preferably with a quantification
of the errors involved, I'm not going to ratify the ideas as
scientifically proper enough to make a theoretic strong point with, let
alone history. Maybe I am actually sorry as a person that there are so
many errors in the often promoted as "perfect" digital signal processing
domain, but that doesn't change anything!
So about that idea (not really of mine) to think about the effect of the
DACs interpolation and smoothing filters: that's real, but still you
need the *properly reconstructed signal* first, and THEN on top of that
make sure the signal wurst-ing that goes on in the DAC comes out the way
you want. Terribly complicated as that seems, to me it's rather basic.
T.
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