== Description ==

2nd order fixed notch filter

Transfer function
Given:
	th = 2 * pi * centralFrequency * samplePeriod
	d = exp(-2 * pi * bandwidth/2.0 * samplePeriod)
	a = ( 1 + d^2) / 2
	b = ( 1 + d^2) * cos(th)

then:
	  z^2 - 2 cos (th) z + 1
  H(z) = a ----------------------
	    z^2 - b z + d^2

Diference equation:
	y(n) - b * y(n-1) + d^2 * y(n-2) = a * x(n)  - a*2*cos(th) * x(n-1) + a * x(n-2)

== Install ==

scons clam_prefix=path/to/installed/clam/prefix
scons install