Digital pulse rebalance accelerometer

Claim 1

A digital pulse rebalance accelerometer for measuring acceleration of a body and comprising: a housing assembly having an elongated inner cylindrical chamber, a primary motor winding disposed around a portion of the inner wall of the chamber for developing a rotational electromagnetic field across said chamber, rotor means having a longitudinal axis coaxial with said chamber and disposed within said chamber for unencumbered rotation and translation, an air gap encompassing said rotor for isolating said rotor from surrounding housing structure, a hysteresis motor ring disposed around a central portion of said rotor and disposed within the plane of said rotationaL electromagnetic field for rotating said rotor, first and second split cup, capacitive, pick-offs encompassing respective first and second end portions of said rotor for responding to changes in capacitance at respective rotor ends, first and second torque coils adjacent respective pick-offs and disposed around the inner annular surface of the chamber encompassing a portion of said rotor for coupling electromagnetic energy to respective ends of said rotor, said rotor being constrained only by the hydrodynamic air gap and electromagnetic forces, said rotor ends having, respectively, a magnetic metal ring forming the terminal end portion for changing the capacitance of said split cups in response to longitudinal motion of the rotor and for providing motor restoration forces in response to electromagnetic energy coupled through said torque coils, a power supply for activating said primary motor winding and thereby imparting rotation to the rotor, differential means coupled to said first and second capacitance pick-off cups for providing differential output pulses in proportion to change in capacitance at the rotor ends indicative of changes in velocity of the housing assembly, a first oscillator and clipper amplifier serially connected between said first capacitive cups and said differential means, a second oscillator and clipper amplifier serially connected between said second capacitive cups and said differential means; and wherein said first clipper amplifier has an output coupled to said second torque coil for coupling electromagnetic energy thereto, and said second amplifier has an output coupled to said first torque coil for coupling energy pulses thereto.