Posted by
Bill VanAlstyne W5WVO on
May 03, 2007; 8:54pm
URL: http://elecraft.85.s1.nabble.com/8-pole-vs-5-pole-I-knew-this-would-happen-tp446796p446818.html
Irrespective of the original source of the term "roofing filter", it seems
clear enough that whoever made it up wanted to imply the idea of protection,
which is the word used in the RSGB document. A ROOF is a first line of
protection against having nearby high-energy stuff from the outside world
(rain, hail, falling rocks and trees) hit you in the head. :-) A ROOFING
FILTER is likewise a first line of protection for the stage that follows it
against nearby high-energy signals hitting it in the head. (Er, the base, or
the gate, or whatever.) Whether it was first used in some marketing brochure
or in an engineering paper, the term nonetheless is aptly descriptive. Since
the concept involved really has to be understood in order for the term to
make sense, however, I tend to lean toward the idea that it was made up by
an engineer. Most marketing guys aren't that smart. Uh, no offense intended.
:-)
Bill / W5WVO
Darwin, Keith wrote:
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