function w = wv_window(n)
% WV_WINDOW  A smooth taper for spectral estimates: sin(pi t)^8 on n points.
%
% The eighth power is deliberate.  Its sidelobes fall off like k^-9, so a
% strong partial ten bins away leaks into a weak one at about 1e-9 of its
% amplitude, which is what lets wv_peakfreq measure a frequency to nine or
% ten digits from a few dozen periods.  The price is a main lobe about five
% bins wide, which only matters when two partials are closer than that.
t = ((0:n-1)' + 0.5) / n;
w = sin(pi * t) .^ 8;
end