  This paper uses the machinery of almost periodic functions to prove that even
without uniform convergence the connection between a pair of almost periodic
functions and the constants of the associated Fourier series exists for both
the convolution and cross-correlation.
  The general results for two almost periodic functions are narrowed and
applied to Ramanujan sums and finally applied to support the specific relation
of the Wiener-Khinchin formula for arithemic functions with a Ramanujan-Fourier
Series.
