Re: Nature of Feedback - Technical

"Chris Hornbeck" <chrishornbeckremovethis@xxxxxxx> wrote in
message news:tlliu1dujltdpeetq2uavu1p6hpbfhuod4@xxxxxxx
On Tue, 07 Feb 2006 17:50:17 -0800, Bob Cain
<arcane@xxxxxxxxxxxxxxxxx> wrote:

Systems *very close* to oscillation act as if they're
non-linear, and cause a lot of confusion (in me too).

Yeah, that statement causes confusion in me too. Huh?

This goes back to the earlier discussion about
whether oscillation was chaotic or linear. You and
Arny convinced me, by weight of conviction, that
oscillation is linear.

Actually, what I said is that it is a linear process in the sense that it
can and does happen when all the elements of the system are linear. It is
also true that until some element of the system becomes nonlinear, feedback
produces pure sine waves.

After all - feedback is how an audio oscillator works. The tricky part of
building an audio oscillator is stabilizing the level of the oscillator.
This requires careful monitoring of the output and rapid precise
modifcations to the loop gain.

Linear systems *very close* to oscillation have several
characteristics of nonlinear chaotic systems:
extreme sensitivity to initial conditions,

I don't see that. All that is required to start oscillation is a little
noise, and noise is universally present in analog systems and itself highly
chaotic. However, the output of an oscillator is not chaotic - it is a pure
tone.

Therefore *any* of a wide range of initial conditions ends up with the same
final condition. The only thing that changes is how long it takes to get
there.



.

Relevant Pages

  • Re: Critical damping of pendulum
    ... >Critical Damping: Critical damping is the smallest amount of damping at ... >that of the linear oscillator. ... preparing a graph of critical damping versus initial displacement. ...
    (sci.physics)
  • Re: Missing Schmitt Gates??
    ... or acting as a frequency-counter front end. ... By now you've probably used one as a crystal oscillator too, ... Kinda like a phase shift oscillator. ... sinusoidally (linearly) and oscillation sustained by linear ...
    (sci.electronics.design)
  • Re: Critical damping of pendulum
    ... > non-linear to the extent that for all non-linear oscillators, ... > that of the linear oscillator. ... If the linearised equation has an oscillatory ...
    (sci.physics)
  • Re: how good are class D amplifiers?
    ... the way they display noise. ... Better than light bulbs, I think. ... In the case of the light bulbs and the thermistors, the response time is set ... allows you to tailor the settling time of the oscillator more ideally. ...
    (uk.rec.audio)
  • Re: strange squelch acting.....
    ... didn't stop direct radiation. ... Noise radiated from telephone lines which have DSL networking ... Harmonic noise generated by a defective oscillator in an Ethernet ... Other people have reported nasty-noisy signals from oscillations in ...
    (rec.radio.amateur.antenna)
Loading