for the output sequence of the filter ys t y s t x s t h k 2 h k in equation 2 represents the pulse response of the filter while k corresponds to the filter length the output signal ys t results therefore from the convolution of the input signal xs t with the pulse response h k of the high pass filter 16 in the rise detector 20 the energy ef t of the segment which is present at that moment which is also called the current segment is first calculated from the filtered input data ys t via a scalar product a comparison with the energy ef t 1 of the segment preceding the current segment and with the energy ef t 2 of the next to last preceding segment then supplies the criterion for the energy rise in the discrete time audio signal from one segment to the next the expression for the first criterion or krita thus reads as follows krita e f t gt k 1 u00b7 e f t 2 lt e f t gt k 2 u00b7 e f krita t 2 gt f t gt e min f 3 in accordance with the usual notation u201c v u201d denotes a logical or operation while u201c u201d denotes a logical and operation the last term.