[Elecraft] K3 - 2.7 kHz Shape Factor

[Geoffrey Mackenzie-Kennedy]

 From Bill Tippett  <btippett at alum.mit.edu>

>From the
>FAQ of Inrad's paper on roofing filters by W2VJN:

>"5. If 6 poles work so well, why not 8 poles?

>Eight poles would provide much better
>stop-band isolation, but it's not required in a roofing filter and would 
>make no
>noticeable improvement in IMD performance."

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A moot point I would suggest Bill when the symmetry (or lack of) a Ladder 
filter's response is also considered. The more poles the better in a Ladder 
roofing filter to improve symmetry provided that the IMD generated within 
the filter does not become a limiting factor, a point that Jack K8ZOA has 
noted. To preach to the choir, filter IMD performance is usually measured 
early on in a receiver's design exercise prior to fixing the Gain 
Distribution.

73,
Geoff
GM4ESD