Re: [Amps] IMD

[Ron Youvan <ka4inm@tampabay.rr.com>]

   Gary Schafer wrote:

> Hi Bill,

> This is not a problem of not producing the square wave itself.
> A perfect square wave has all of the odd harmonics in phase.
> When you modulate an SSB transmitter with a square wave the phase of the
> fundamental and harmonics shift. This produces another fundamental that sums
> together.

   This "different delay for different frequencies" is called "group delay."
It is something that messes up dial up modems.  (so you don't get 56 kB/s)

> To pass an ideal square wave signal in an SSB transmitter requires infinite
> bandwidth and infinite amplitude. Though the square wave is not the ideal
> one it still requires a high amplitude capability.

> This is pointed out in the Collins "fundamentals of SSB".
> Here is a link to an article on the subject by Wes Stuart N7WS.
-- 
    Ron  KA4INM - Did you know ...
                  ... that no-one ever reads these things?
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