  This work focuses on moderate deviations for two-time scale systems with
mixed fractional Brownian motion. Our proof uses the weak convergence method
which is based on the variational representation formula for mixed fractional
Brownian motion. Throughout this paper, Hurst parameter of fractional Brownian
motion is larger than $1/2$ and the integral along the fractional Brownian
motion is understood as the generalized Riemann-Stieltjes integral. First, we
consider single-time scale systems with fractional Brownian motion. The key of
our proof is showing the weak convergence of the controlled system. Next, we
extend our method to show moderate deviations for two-time scale systems. To
this goal, we combine the Khasminskii-type averaging principle and the weak
convergence approach.
