A filtering method and a filter are disclosed. The method includes integrating values of an input signal by an integrator comprising a memory; storing an integration value in the memory; cyclically resetting the memory after integrating a first predefined number of values of the input signal; in a steady operating mode, generating a value of an output signal based on the integration value stored in the memory each time after integrating the first predefined number of values of the input signal; and in an initial operating mode, generating an initial value of the output signal based on the integration value stored in the memory after integrating a second predefined number of values of the input signal, wherein the second predefined number is smaller than the first predefined number.