Broad-band colored noise: Digital simulation and dynamical effects

We propose a broad-band colored noise, which allows the transition between ''red'' and "green" noises. A double-integral algorithm for solving the Lan gevin equation with this noise is developed. The steady currents of an over damped particle moving in the correlation and diffusion ratchets are calcul ated. It is shown that the flow reverses sign when the external noise is fi ltered off in the region of low frequencies to a sufficient extent. The pre sent noise is also compared with the Ornstein-Uhlenbeck colored noise and t he harmonic noise. [S1063-651X(99)12112-3].