The present disclosure generally relates to internal combustion engines. The teachings thereof may be embodied in methods for the measuring of a feedback signal generated by the movement dynamics of a fuel injector in operation. A method may include: (a) generating an electrical test pulse; (b) feeding the test pulse into an actuation line connecting the output stage to the injector to an electric drive of the injector; (c) measuring an electrical response pulse generated by the actuation line in response to the test pulse; (d) identifying a characteristic feature of the measured response pulse; (e) transferring the feature to a control and evaluation unit; (f) evaluating the feature; and (g) acquiring the characteristic information item about the measuring channel based on the evaluation of the transferred characteristic feature.