A transmitter includes a fractional N synthesizer, a baseband digital modulation stage coupled to the fractional N synthesizer in a first modulation mode, and a baseband IQ modulation stage also coupled to the fractional N synthesizer and reusing the fractional N synthesizer in a second modulation mode. Displays showing the contents of play lists are arranged and displayed so that the contents become continuous in sequence in a playback sequence from content that is currently being played back from a display of an operation element that causes an image of a playback process to appear or from a display showing the content which is currently being played back. In the preferred embodiment the ultrasonic welding apparatus includes a sonotrode removal mechanism for extracting the sonotrode from the reed. The invention provides a transmitter and a receiver for implementing the method.