Hop Sizes for WOLA

In the weighted overlap-add method, with the synthesis (output) window equal to the analysis (input) window, we have the following modification of the recommended maximum hop-size table:

L	In and Out Window (Length $M$ )	$R_{\hbox{max}}$	$R_{\hbox{\hbox{\sc Cola}}}$
1	Rectangular ($L=1$ )	M/2	M
2	Generalized Hamming ($L=2$ )	M/6	M/3
3	Blackman Family ($L=3$ )	M/10	M/5
L	$L$ -term Blackman-Harris	M/(4L-2)	M/(2L-1)

Note that the following properties hold as before in the OLA case:

• $R_{\hbox{max}}$ is equal to $2\pi$ divided by the main-lobe width in ``side lobes'', while

• $R_{\hbox{\hbox{\sc Cola}}}$ is $2\pi$ divided by the first notch frequency in the window transform (lowest available frame rate at which all frame-rate harmonics are notched).

• For windows in the Blackman-Harris families, and with main-lobe widths defined from zero-crossing to zero-crossing, $R_{\hbox{\hbox{\sc Cola}}} = 2 R_{\hbox{max}}$ .