Blackman-Harris Window
A weighting that is applied in the time domain to reduce leakage within a Fourier Transform analysis.
The Blackman-Harris windows are a family of three and four term windows. The variations on the coefficients allow a trade between main-lobe width and side-lobe level.
3 term -67dB side-lobe
where
w(t) = weighting as a function of time
t = time
N = total length of window
3 term -61dB side-lobe
4 term -92dB side-lobe
The Blackman-Harris window has much the same performance as the Kair-Besl window, except that it suppres the sidelobes more than 92dB at a cost of an 11% wider noi bandwidth.
In the time domain this function is shown below:
The frequency respon of this window is shown along with that of a rectangular window
for comparison:
4 term -74dB side-lobe
