Abstract: A method of controlling a two-phase stepping motor to operate in one of a plurality of operating modes in which output of the motor behaves differently upon encountering obstacle, comprises the steps of: generating an electrical driving current comprising a repeating series of a positive active driving region, a first inactive driving region, a negative active driving region and a second inactive driving region; determining one of the duration of the active driving regions and the duration of the inactive driving regions relative to the other of the durations to thereby cause the motor to operate in a corresponding mode of the operating modes; and applying the driving current to the motor.

Abstract: A process for the preparation of hermetically sealed electronically active microstructures involves the preparation of a plurality of microstructures and associated conductive paths and lead bond areas on a single wafer such that areas surrounding the microstructures are maintained in a planar condition. A second wafer having a plurality of microstructure-receiving cavities is placed atop the first wafer and fusion or anodically bonded. The microstructures are preferably connected to lead bond pads which lie outside the surround, the second wafer also having bond pad accessing through-holes to facilitate bonding electrical leads to the devices after sawing from the wafer. The lead-connected devices may be further encapsulated by injection molding, potting, or other conventional encapsulative packaging techniques.

Abstract: An asynchronous time-hopping multiple access "(ATHMA") protocol and a simplex mode communication system utilizing the same requires no synchronization between transmitting stations, no handshaking between transmitters and receivers and no system manager to coordinate data message transmission. The ATHMA protocol ensures that for an n-channel asynchronous simplex mode communication system, each transmitter repeatedly sends each unique data message n successive times according to its own time-hopping schedule. In the preferred embodiment the time-hopping schedules are coordinated such that at least one duplication of each unique message will not collide with any other messages over a given period. Thus, at most n-1 transmissions out of the total n transmissions of each unique data message will be collided and lost. The ATHMA protocol and communication system of the present invention is ideally suited for applications requiring a low throughput rate and channel capacity.