A method for identifying of and distinguishing between at least two predetermined different disturbance states in an inkjet print head, the method comprising: a) providing a disturbance identification input signal (u); b) applying the disturbance identification input signal to an actuator, the actuator being part of an ejection unit of an inkjet print head; c) receiving a residual pressure wave output signal (y); and d) analyzing the residual pressure wave output signal; characterized in that the step d) of analyzing comprises: d1) designing and providing a respective mathematical analysis operator (G n on) for each predetermined disturbance state (n); d2) executing each respective mathematical analysis operator using the received residual pressure wave output signal as an input for each respective mathematical analysis operator; d3) comparing an output (v n) of each respective mathematical analysis operator to a respective predetermined output reference; d4) deciding for each predetermined disturbance state whether the disturbance state is present, wherein it is decided that a corresponding disturbance state is present, if an output of a respective mathematical analysis operator corresponds to the respective predetermined output reference; and it is decided that a corresponding disturbance is not present, if an output of a respective mathematical analysis operator does not correspond to the respective predetermined output reference. a) providing a disturbance identification input signal (u); b) applying the disturbance identification input signal to an actuator, the actuator being part of an ejection unit of an inkjet print head; c) receiving a residual pressure wave output signal (y); and d) analyzing the residual pressure wave output signal; characterized in that the step d) of analyzing comprises: d1) designing and providing a respective mathematical analysis operator (G n on) for each predetermined disturbance state (n); d2) executing each respective mathematical analysis operator using the received residual pressure wave output signal as an input for each respective mathematical analysis operator; d3) comparing an output (v n) of each respective mathematical analysis operator to a respective predetermined output reference; d4) deciding for each predetermined disturbance state whether the disturbance state is present, wherein it is decided that a corresponding disturbance state is present, if an output of a respective mathematical analysis operator corresponds to the respective predetermined output reference; and it is decided that a corresponding disturbance is not present, if an output of a respective mathematical analysis operator does not correspond to the respective predetermined output reference. d1) designing and providing a respective mathematical analysis operator (G n on) for each predetermined disturbance state (n); d2) executing each respective mathematical analysis operator using the received residual pressure wave output signal as an input for each respective mathematical analysis operator; d3) comparing an output (v n) of each respective mathematical analysis operator to a respective predetermined output reference; d4) deciding for each predetermined disturbance state whether the disturbance state is present, wherein it is decided that a corresponding disturbance state is present, if an output of a respective mathematical analysis operator corresponds to the respective predetermined output reference; and it is decided that a corresponding disturbance is not present, if an output of a respective mathematical analysis operator does not correspond to the respective predetermined output reference.