  The simplicity of a question such as wondering if correlations characterize
or not a certain system collides with the experimental difficulty of accessing
such information. Here we present a low demanding experimental approach which
refers to the use of a metrology scheme to obtain a conservative estimate of
the strength of frequency correlations. Our testbed is the widespread case of a
photon pair produced per downconversion. The theoretical architecture used to
put the correlation degree on a quantitative ground is also described.
