Abstract: A torque motor for rotatably driving a rate sensor (10, 100) which includes a permanent magnet (30) that is magnetically coupled to an upper rotor (18, 106) and a lower rotor (44, 110). At three sites, the upper rotor includes an upper tab (60), which is centered between two electromagnetic coils (56, 58). Similarly, at each site, the lower rotor includes two lower tabs (62) that extend adjacent opposite faces of the electromagnetic coils. With no electrical current flowing through the electromagnetic coils, flexures (46) that connect the upper and lower rotors to a base (12) provide a spring bias force sufficient to maintain the upper tab centered in a slot (66) and thus, equidistant between each of the two lower tabs. As the electric current flows through the electromagnetic coils, distribution of the magnetic flux produced by the permanent magnet changes so that the upper tab is attracted toward one of the electromagnetic coils and repelled from the other.

Abstract: A data processing system for use in a solid state flight data recorder wherein a plurality of aircraft parameter signals are processed and stored in electronic memory for later retrieval. The processor identifies those aircraft parameter data signals to be stored and for each such datum signal produces a signal triplet comprised of a parameter label signal, a time tag signal representative of the time interval from a reference time within which the data signal was produced, and the datum signal. A frame of the data bit stream produced by the data processor for storage in the memory includes an initial reference time signal followed at fixed intervals by time tick signals. Each signal triplet is positioned in the data bit stream following that initial reference time signal or time tick signal to which its time tag signal is referenced. By so tiering the data time formatting a substantial compression of data is realized thereby reducing memory size requirements.