A miniature, unmanned aircraft for acquiring digitized data, transmitting digitized data, or both, having an electrical supply system capable of sustained operation. The extrusion resistant ring in combination with an elastomeric diaphragm provides a high pressure seal for down-hole oil drilling apparatus. The selectively removable frame can adapt to conform to at least one of the width or height of the land vehicle, and can be secured thereto by a securement assembly. It is therefore possible to suppress chatter vibration during machining and is possible to reduce roughness of a cut surface of a work material. The two non-overlapping pulses are a single pair of clock pulses which facilitate AC self-test timing analysis of the logic system. Sensing is performed on signals in the group and adjacent signals are either switched or delayed if the adjacent signals are switching at the same time.