the information can be interpreted from at least intrinsic FDFs. If the information is not available from intrinsic FDFs, it is impossible to obtain the information from observed FDFs. A simple model such as global magnetic-fields only and/or Kolmogorov-like turbulent magnetic-fields does not allow us to address this question, and a study of intrinsic FDFs based on realistic galactic models is necessary.

In this paper, we investigate intrinsic FDFs of galaxies in detail with a latest galactic model [@arkg13] which based on observational data of the Milky Way and incorporates three dimensional magneto-hydrodynamic (MHD) turbulence. Observed FDFs are not simulated in this paper. We demonstrate how properties of a galaxy are reflected into the intrinsic FDF, and show some statistical quantities to characterize global shapes of FDFs for different galactic models. In section \[section:2\], we describe the basic idea of Faraday RM synthesis and method to calculate the FDFs using galactic models. The resultant FDFs and their characterization are presented in section \[section:3\]. Discussion and summary of our results follow in section \[section:4\].

Calculation Method {#section:2}
==================

Faraday RM Synthesis {#subsection:2.1}
--------------------

In this section, we explain Faraday RM synthesis first proposed by [@bu66] and extended by [@br05]. The complex 