The disclosed vacuum assembly can be mounted in a vehicle. The acquisition time and hardware complexity of one technique scale as O, where N denotes the number of frequency bins acquired. The first classification value and the second classification value being indicative of whether the e-mail message is spam. Methods for producing a smoothly stepped etalon and for smoothing the step transitions in an abruptly stepped etalon are also disclosed. The memory unit is designed as a read-write memory.