Figure 3: Schematic diagram of computation procedure. , and are the points of peaks detected by . The time difference between and is shown by the summed signals and . Notice that the secondary peaks before and after the summed peaks are smaller than the central peak in (“*” in ) because the summed signal of negative peaks are also summed after the reversed calculation (calculation of the signal “· (−1)”). The simultaneously summed signal from the compared channel ( ) shows a similar waveform, but the phase is shifted from .