Jeff Liebermann wrote in
:

Without a
reflection, there can be no standing waves.


That's the one bit that comes naturally to my own understanding, such as it
is. How far does this parallel with an optical laser cavity? I'd find it
easier to understand if someone here who knows both can point out a few
essential similarotes and differences.

Also, in the ringing of a resonant audio filter (or any electronic filter),
there seem to be parallels there too. After all you can only have ringing, a
note produced, while energy remains in the system.

On Sat, 01 Nov 2014 16:05:53 -0500, Lostgallifreyan
wrote:

Jeff Liebermann wrote in
:

Without a
reflection, there can be no standing waves.

That's the one bit that comes naturally to my own understanding, such as it
is. How far does this parallel with an optical laser cavity? I'd find it
easier to understand if someone here who knows both can point out a few
essential similarotes and differences.

Sigh... topic drift again.

The parallel with a longitudinal mode laser cavity is fairly close.
http://en.wikipedia.org/wiki/Longitudinal_mode
The transmission line is some multiple of 1/2 wavelength long. The
signal bounces back and forth between the ends, reinforcing itself
with every bounce, until it spews forth from from one end or edge.
Obviously, without reflections, there would not be any laser action.

Also, in the ringing of a resonant audio filter (or any electronic filter),
there seem to be parallels there too. After all you can only have ringing, a
note produced, while energy remains in the system.

Not quite. If you apply energy to a resonant circuit (electrical or
mechanical), that then remove the input, you'll get a damped wave
(i.e. exponential decay) output where the rate of decay is determined
by the losses in the system. You could build a transmission line
oscillator, which would exhibit some rather small damped wave output
when turned off, but in most cases, there's no connection with
reflected or standing waves because there is usually no transmission
line.

Might as well be part of the problem. What I do in my spare time. I
recorded these in about 1998. Please forgive my screwups, plagerism,
lack of coherent style, sloppy fingering, etc:
http://802.11junk.com/jeffl/music/


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote in
news
Not quite. If you apply energy to a resonant circuit (electrical or
mechanical), that then remove the input, you'll get a damped wave
(i.e. exponential decay) output where the rate of decay is determined
by the losses in the system. You could build a transmission line
oscillator, which would exhibit some rather small damped wave output
when turned off, but in most cases, there's no connection with
reflected or standing waves because there is usually no transmission
line.


Well, doesn't that still mean there's energy there to power that decay? I get
the exponential bit (had to explore that a lot to code a synth. so the
energy never entirely vanishes, sort of like half-life in fissile materials.

Point taken about usually no transmission line. I remember CB'ers talking of
SWR meters and aiming for as little standing wave as possible. That seems to
go with what Jim (Pennino) said about not having a standing wave without a
transmission line.

Might as well be part of the problem. What I do in my spare time. I
recorded these in about 1998. Please forgive my screwups, plagerism,
lack of coherent style, sloppy fingering, etc:
http://802.11junk.com/jeffl/music/


Nice. Though you do what I tend to do, caught in a singular sort of chord
sequence, expression, whatever it is. I got it from listening to Tangerine
Dream. It's a nice trap (and yours is more elegant than mine too) but it is a
trap. I found a way out of it though, if I can make the effort and maintain
the habit... When walking, I hum, or whistle, and the tunage is far more
varied than when I'm in front of an instrument. I have a small USB memoery
thinger with audio recording (and annoyingly short battery life) that I
usually fail to carry with me. Shame, because a couple of days ago I
improvised for about a half hour on a Cuban tune, 'Chan Chan', very
effectively, and had never done that before. The more I learn about Beethoven
and Schubert, the more I hear about how good they were at improvisation! Most
people seem to think that 'vclassical' was all ablout written formalism. Of
course it wasn't... it was closer to jazz in the sense that it was about
capturing improvisation. Their skill was in doing exactly that. Mozart heard
Allegri's 'Misereri' at one sitting, and recalled enough to write it down
later. I can't do that, but with a bit of technical help (if I can be
bothered to persist in using it), I might make a few things, at least enough
to test the instrument I'm trying to byuild. I have no web storage, but if
you're interested I can try to put three of four bits into a Usenet test
binary group somewhere.. They're not very elaborate, just a few very varied
ideas.