Re: Modulation

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

I made a typo in this piece so I'll correct it before I get jumped on:

On 17 Jul 01, at 17:19, Tesla list wrote:

> Original poster: "Malcolm Watts by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> Hi all,
>          I've had this crazy idea kicking around for several years 
> and done nothing about it so I thought I'd put it to the list before 
> someone else did. It was sparked (npi) by my thinking about the 
> sideband issue which I replied to the other day.
> 
>      The nub of the idea is to audio modulate a sparkgap coil. Sounds 
> crazy, right? (NY parlance ;)  Thinking about it resulted in this 
> train of thought: we know that the coupling constant and resonant 
> frequency of the coil sets the sideband frequencies. We also know 
> that k is a pure function of geometry. That suggests that the only 
> way to alter the sideband frequencies (by proxy the modulation 
> frequency) is to alter k, in other words, mechanically alter the 
> proximity/positioning of the secondary relative to the primary. That 
> amounts to moving the secondary with some kind of voicecoil 
> arrangement (possibly using turns on the secondary itself as the 
> motor winding).
>      BUT, if there was some other way k could be altered that didn't 
> involve moving one of the coils, the goal could be met. If it could 
> be done, one would want air streamers only from the secondary to 
> largely preserve the loaded Q of the system. Sort of a giant ion 
> speaker. Inserting a third coil coupled to the pri-sec with its 
> loading electronically controlled might do the trick although that 
> would alter Ksys which wouldn't be terribly desirable. Question - 
> does such an arrangement alter K or does it just alter M?

That second to last last line should have read "would alter *Qsys* 
....."   Of course I want to alter Ksys.

Malcolm
 
>      Any ideas from the mathematicians on the list?
> 
> Malcolm
> 
> 
> 
>