Survey window function
= Survey window function
{title2=$W(\mathbf x)$}
A survey window function describes the finite spatial coverage and weights of a <galaxy survey>. Multiplication by this window in position space mixes <Fourier modes> by convolution in <Fourier space>. A dimension of extent $L$ cannot robustly measure wavelengths much larger than $L$; the fundamental <wavenumber> of a periodic box of that size is $2\pi/L$.