Window Definition:

$$w_{BH}(n)= w_R(n)\sum_{l=0}^{L-1} \alpha_l \cos( l \Omega_M n), \protect$$ (4.3)

where $\Omega_M\isdef 2\pi/M$, and $w_R(n)$ is the length $M$ zero-phase rectangular window (nonzero for $n\in[-(M-1)/2,(M-1)/2]$).