  It is shown how to decorrelate the (prewhitened) power spectrum measured from
a galaxy survey into a set of high resolution uncorrelated band-powers. The
treatment includes nonlinearity, but not redshift distortions. Amongst the
infinitely many possible decorrelation matrices, the square root of the Fisher
matrix, or a scaled version thereof, offers a particularly good choice, in the
sense that the band-power windows are narrow, approximately symmetric, and
well-behaved in the presence of noise. We use this method to compute band-power
windows for, and the information content of, the Sloan Digital Sky Survey, the
Las Campanas Redshift Survey, and the IRAS 1.2 Jy Survey.
