For an observer for estimating the internal effective torque of a torque generator, which can also process unfiltered and noisy measurement signals and which is capable also of mapping vibration effects in the estimated effective torque, there is provision that for a dynamic system an observer (UIO) is designed with observer matrices (N, L, G, E, Z, T, K, H) and with an unknown input w, and the observer (UIO) receives at least one noisy measurement signal of the input vector u and/or the output vector y, and which observer estimates the status vector (x̂) and the effective torque (TE) therefrom as an unknown input in that the matrix (N, Z), which determines the dynamic of the observer error (ė) as a difference between the status vector (x̂) and the estimated status vector (x), is configured in such a way that the intrinsic values (λ) of this matrix (N, Z) lie in a range f2/5 > λ > 5⋅f1, wherein f1 is the maximum to be expected change frequency of the at least one measurement signal, and the noise in the at least one measurement signal influences the frequency band which is greater than the frequency f2.