A content player includes a pausable mass storage device player that can be used to record and play content. A phase-sensitive frequency-domain representation of the input analog waveform is recorded. The second area and its portion are essentially made in a first cavity configured to focus in the first cavity at least one portion of the electromagnetic radiation. Then the average pressure value, the average flow rate value, a new compensation factor and a new cracking pressure are used to determine a theoretical flow rate for controlling the pressure regulating device and producing a pressure corresponding to the target flow rate. An authenticity feature which can be reliably verified by machine or by humans and which can moreover not be deceptively imitated by copying technology is realized by an electro-optical andor acoustic display device integrated in the value document.