[AMPS] Clarification and correction

Arlen Mendelssohn pcmeas@hotmail.com
Mon, 18 May 1998 07:19:52 PDT


How do you do it?  I was on sojourn for four days, and upon my return 
and login, am greeted with over three hundred emails from the reflector?

I believe I should clarify things which I have not been clear on.  I do 
not have a BSEE; I studied engineering for a few years, then received 
degrees in history and music, with later graduate work in the 
humantities.  Thus, my electronics knowledge is from advancing that 
which I acquired in a few years, and hands-on experience.  In theory, I 
have an MSEE, but it was awarded, and not deserved.  The wonders of the 
electronics world I have had to experience purely as a consultant, 
although as such I have been a contractor to many truly wonderful 
companies.  So I do not consider my word "exact" by any means.  I am 
open to other theories, but I will measure those theories against the 
understanding of physics that I did gain in my few years in school.

I will not point out the gentleman's name or call, as he communicated 
via direct email and I have not seen the callsign on here, but it has 
been pointed out to me where IMD products do not have to arise from 
existing harmonics.

In the Taylor series expansion of a two-tone signal applied to a 
nonlinear device, the term arises

((sin 2f1(t) + sin 2f2(t))^3

That's it, right there.  When this term is expanded, IMD frequencies are 
noted to be present.  

I had jumped to a conclusion: since forcing the second harmonic of a 
device back to the device in the correct phase will substantially reduce 
third order IMD, I assumed this demonstrated that the presence of the 
second harmonic was required.  Mathematically, this is clearly not true.

Regards, Gents,


Get Your Private, Free Email at http://www.hotmail.com

FAQ on WWW:               http://www.contesting.com/ampfaq.html
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm