An apparatus for supplying a respiratory gas to a patient within the scope of the diagnosis and/or the treatment of sleep-related breathing disorders includes an electronic signal processing device for generating a pressure control signal on the basis of indicative signals relating to the breathing activity and/or the physiological state of a person. The signal processing device comprises a signal inputting device and an extraction device for generating data field entries according to predefined signal analysis procedures. A pressure signal generator is provided for generating the pressure control signal, taking into account determined data field entries which are at least selected by the extraction device.