  We investigate the effect of the window function on the multipole power
spectrum in two different ways. First, we consider the convolved power spectrum
including the window effect, which is obtained by following the familiar (FKP)
method developed by Feldman, Kaiser and Peacock. We show how the convolved
multipole power spectrum is related to the original power spectrum, using the
multipole moments of the window function. Second, we investigate the
deconvolved power spectrum, which is obtained by using the Fourier
deconvolution theorem. In the second approach, we measure the multipole power
spectrum deconvolved from the window effect. We demonstrate how to deal with
the window effect in these two approaches, applying them to the Sloan Digital
Sky Survey (SDSS) luminous red galaxy (LRG) sample.
