Systems and methods for identifying a motion state of a mobile device are disclosed. Preferably, the optical splitter is tuneable to direct at least part of the optical power from the optical source to each of the first and second paths, in varying proportions. Each of the comparison units has a positive output and a negative output, and the digital signal is generated by the negative output and the positive output of the comparison units in a differential way. The NAM element can be interconnected with other NAM elements to form a larger NAM storage device. The isolation region is positioned in a trench that is formed with first and second etching process in which the latter etches different crystallographic directions of a single-crystal semiconductor material at different etch rates. Selectable lists are configurable by the user of the mobile communication device, whereas fixed list types cannot be changed by the user of the mobile communication device.