1. A method for digital recursive filtering an input signal according to a rational filter transfer function clocked by a clock signal comprising the following steps: (a) providing first and second order rational functions corresponding to the rational filter transfer function; wherein the following steps are performed iteratively: (b1) determining a plurality of intermediate signals from the input signal using the first and second order rational transfer functions and one or more previous intermediate signals determined in a preceding clock cycle of the clock signal; (b2) adding the plurality of intermediate signals to generate at least one filter output signal wherein the filter output signal corresponds to the rational filter transfer function.