Re: (Fwd) RE: Longitudinal Waves

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<davep-at-quik-dot-com>
> 
> > The fact that nobody has explained precisely how the energy is added
> > to the wave to keep it oscillating as a sine wave is what will keep
> > me on my current theory.
> 
>         Random energy added to a resonant system (acoustic or electrical)
>         tends to add to the resonant system.  This is well known and
>         well understood.  Mutual inductance (transformer action)
>         is a most usual and convenient and conventional way to accomplish
>         this.

	Not sure what you mean by random; to me that implies you can provide an
impulse at random times with respect to an individual cycle.  The
excitation must be synchronous with the oscillation of the system, and
added in the correct phase on each cycle.  Simplest example would be
pumping a swing - you have to have the correct timing.

Ed