"A still-smoother weighting function that is easy to program is called the Hann window. The Hann window is often described as a “sine squared” distribution, although it is easier to program as a cosine subtracted from unity. The shape of the coefficient outline looks like a sinewave whose valleys are at the ends of the array and whose peak is at the center of the array. This configuration offers a smooth window transition from the smallest coefficient amplitude to the largest coefficient amplitude."
ROC = (Length / 2*math.pi)*(Filt - Filt[1])
should be:
ROC = (Length / (2*math.pi))*(Filt - Filt[1])