> Date: Tue, 2 Sep 2008 00:43:00 -0700
> From: [EMAIL PROTECTED]
> To: [email protected]
> Subject: need math help
>
> Man, my math skills are getting kinda dusty.
>
> I've got a function of p (written in c)
> f = pow(p, (log 0.5)/log m)
> where m is a parametric constant 0<=1.
> It /can be shown/ that f is also in the range [0,1]
>
> What does this function look like? It seems that it _shouldn't_ be that
> hard, but I find my head won't seem to work.
>
> I know what it is for some values of m:
> for m=approaching 0 f=> p**0 = 1
> for m=0.5, f= p**1 = p
> for m=approaching 1, f= p**-BIG => 0
Your last point is partially wrong. as m approaches 1, log m approaches 0,
from the negative side. log .5 is -.301. So -.301/an infinitely small
negative number is a very large positive number, not a very large negative
number. Your result is right though, it approaches 0.
This looks like a bandwidth filter to me. Did I guess right? If so, unless
you're trying to improve it or pick the best filter you don't really need to
know the exact shape, the important part is a rapid decrease once you get out
of the bandwidth. So the general shape is 1 at the center, slowly decreasing
to the band wanted (.5), followed by a rapid decrease towards 0. An ideal
filter would be exactly 1 from [0,.5], and 0 from [.5,1]. You only get ideal
ones with digital data though.
Gabe
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