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