Abstract: A sensor (10) is disclosed for measuring the specific force and angular rotation rate of a moving body and is micromachined from a silicon substrate (16). First and second accelerometers (32a and b) are micromachined from the silicon substrate (16), each having a force sensing axis (38) and producing an output signal of the acceleration of the moving body along its force sensing axis (38). The first and second accelerometers (32a and b) are mounted within the substrate (16) to be moved along a vibration axis (41). The first and second accelerometers (32a and b) are vibrated or dithered to increase the Coriolis component of the output signals from the first and second accelerometers (32a and b). A sinusoidal drive signal of a predetermined frequency is applied to a conductive path (92) disposed on each of the accelerometers.

Abstract: A vibrating beam force transducer is comprised of an oscillating sensing element having a frequency output indicative of the force applied to the sensing element. The sensing element has a variable electrical resistance which can vary in accordance with temperature fluctuations over the operating range of the transducer.A drive circuit is electrically coupled to the sensing element for causing the sensing element to oscillate at a resonant frequency that is a function of the force applied to the sensing element. The drive circuit includes a source of DC voltage, which is utilized for altering the electrical characteristics of the drive circuit in response to variations in the electrical resistance of the sensing element.

Abstract: A non-linear range scale for a radar system is implemented whereby the full range capability of the system is shown with emphasis on close-in targets. The arrangement is adaptable to a variety of non-linear functions having the advantage of selection by the user to provide good close-in visibility and visibility of distant conditions simultaneously.

Abstract: A vibrating beam accelerometer contains an inner structure having a vibrating beam extending between a pair of isolator masses which are connected via isolator beams to a pair of structures, an outer structure having flexure beams extending between a mount structure and a proof mass structure and a peripheral seal structure surrounding said inner structure and said outer structure. Seal plates containing a ring of glass frit material sandwich the above assembly. An electrode pattern termination extends from the above assembly, through the ring of glass frit material, to electronic circuitry containing an oscillator.

Abstract: A MODFET structure having a semi-insulating substrate overlayed with an undoped semiconductor buffer layer of a first composition. The buffer layer is overlayed with an undoped semiconductor layer having a second composition different from the composition of the buffer layer. An etch stop layer having a composition different from the composition of spacer layer is formed on the spacer layer, which in turn is overlayed with a doped semiconductor layer having the same composition as the spacer layer. A gate well is selectively etched through the doped semiconductor layer using a gate mask and is terminated at the top surface of the etch stop layer. In a first embodiment, a gate electrode is deposited on the surface of the stop layer at the bottom of the gate well. In an alternate embodiment the etch stop layer at the bottom of the gate well is removed and a thin dielectric layer is formed between the spacer layer and the gate electrode.

Abstract: A process for producing a cobalt silicide T-gate on a silicon substrate (10) in which a silicon oxide gate layer (12) is formed in the silicon substrate (10). The silicon oxide gate layer (12) is covered with a polysilicon layer (14) and a masking oxide layer (16). An opening (18) is formed in the masking oxide layer (16) through to the polysilicon layer (14) which defines a gate region (22) for the device being fabricated (16). A cobalt layer (20) is deposited on the masking oxide layer (16) and the surface of the polysilicon layer (14) in the gate region (22). The substrate (10) is then heated to react the cobalt layer (20) with the polysilicon layer (14) to form a cobalt silicide layer (24) in the gate region (22). The unreacted portion of the cobalt layer (20) and masking oxide layer (16) are removed and the polysilicon layer (14) etched using the cobalt silicide layer (24) as a mask.

Abstract: A sensor (10) is disclosed for measuring the acceleration and angular rotation rate of a moving body and is micromachined from a silicon substrate (16). First and second accelerometers (32a and b) are micromachined from the silicon substrate (16), each having a force sensing axis (38) and producing an output signal of the acceleration of the moving body along its force sensing axis (38). The first and second accelerometers (32a and b) are mounted within the substrate (16) to be moved along a vibration axis (41). The first and second accelerometers (32a and b) are vibrated or dithered to increase the Coriolis component of the output signals from the first and second accelerometers (32a and b). A sinusoidal drive signal of a predetermined frequency is applied to a conductive path (92) disposed on each of the accelerometers.

Abstract: Apparatus is disclosed for measuring the specific force and angular rotation rate of a moving body. A silicon substrate has first and second substantially planar and substantially parallel surfaces. An accelerometer is formed of the substrate and has a force sensing axis. An output signal is provided which is indicative of the moving body along the force sensing axis. The accelerometer is mounted so as to be movable along a vibration axis perpendicular to the force sensing axis. The accelerometer is driven so as to impart a dithering motion thereto of a predetermined frequency along the vibration axis. The accelerometer includes a frame, a proof mass and a hinge interconnected between the frame and the proof mass for rotating the proof mass about a hinge axis when the moving body is subjected to a force along the force sensing axis.

Abstract: A vibrating tine resonator having a unitary body cut from flat, planar crystalline stock includes spaced apart end portions and a tine system extending between said portions. The tine system includes a pair of similar tine arrays extending side-by-side between base portions. Each array includes a pair of tines extending parallel to one another and defining a slot separating each adjacent pair of tines. Each array also includes a bridge portion spanning the slot and joining the tines. The resonator is excited to operate in a dynamic mode including both a torsional motion component and also a normal motion component. The bridge portion interconnecting adjacent tines is pivoted around an axis parallel with the tines. The tines are also moved to vibrate in directions normal to the flat plane of the resonator body.

Abstract: An arrangement using sensing coils for obtaining flux rate of change information in a magnetic circuit. The arrangement can be used for vibration attenuation in a magnetic forcer system. Active (electric powered) circuitry is used to implement closed loop control of flux rate. The control loop is "broadband" since a broad range of vibration frequencies are attenuated. The arrangement can be applied to magnetic forcer/suspension systems in which vibrations due to magnetic mechanical/magnetic runouts, system mechanical resonances, or external vibration sources are present. The arrangement is particularly applicable for systems with a large number of varying vibration frequencies.

Abstract: A ring laser gyroscope functions both as a standard gyroscope and as an accelerometer. As the ring laser gyroscope experiences acceleration along its input axis, the frame bends and position sensing photodiodes are utilized to detect the optic axis motion and laser beam intensity. By measuring optic axis shifts along the gyro input axis during acceleration, a signal proportional to acceleration is obtained.

Abstract: A vibrating disc transducer assembly suitable for accurately measuring high pressures utilizes a transducer having a vibratory disc that is preferably fabricated from silicon and excited to vibrate in the thickness-shear mode. The excitation is accomplished by placing the resonator in a magnetic field and passing an electric current through electrodes on opposite sides of the disc. The transducer is supported in a housing that communicates with the medium whose pressure is being measured.

Abstract: A turbine engine start system accepts either AC or DC and performs power conversion for multiple functions such as starting an AC synchronous generator as a synchronous motor without degradation of input power quality and with minimal generation of EMI. The system utilizes common magnetic components and common semiconductor transistors and rectifiers within its four major subcircuits. The four major subcircuits include a transformer rectifier, a boost converter, a voltage source inverter and a field excitation controller.

Abstract: A two degree of freedom gyroscope having a drive motor (20), with a permanent magnet rotor (22), which comprises a sensing coil (32) looped around the permanent magnet rotor (22) and disposed in a plane orthogonal to a null spin axis, a torquer coil looped around the permanent magnet rotor (22) and disposed in a plane orthogonal to the null spin axis, and torque drive elements (62, 64, 65) responsive to the signal induced in the sensing coil (32) when the actual rotor (22) spin axis is displaced from the null spin axis (28) for providing current to said torquer coil (34) to urge the axes to coincide. Demodulators (70, 72) can be provided for providing output information in an X-Y coordinate format which is indicative of the actual input angular rates about corresponding axes.

Abstract: A mechanically self-stabilized cavity length controller for use within a ring laser gyroscope, including piezoelectric elements which are employed to move mirrors and effect a change of the laser path length. More particularly, a cavity length controller consisting of component parts fabricated from dissimilar materials, and configured so as to largely cancel any thermally-induced dimensional variations by virtue of the differential thermal expansion rates of the various component parts. The cavity length controller also includes two piezoelectric plates affixed to opposite sides of a deformable diaphragm which is coupled to a mirrored surface within the cavity. To correct for any nominal, thermally-induced cavity variations which might still be evident in a cavity employing the controller, an electrical potential is applied to the piezoelectric plates, causing the radial expansion of one plate and the simultaneous radial contraction of the other, thereby deforming the diaphragm.

Abstract: A sensor (10) is disclosed for measuring the specific force and angular rotation rate of a moving body and is micromachined from a silicon substrate (16). First and second accelerometers (32a and b) are micromachined from the silicon substrate (16), each having a force sensing axis (38) and producing an output signal of the acceleration of the moving body along its force sensing axis (38). The first and second accelerometers (32a and b) are mounted within the substrate (16) to be moved along a vibration axis (41). The first and second accelerometers (32a and b) are vibrated or dithered to increase the Coriolis component of the output signals from the first and second accelerometers (32a and b). A sinusoidal drive signal of a predetermined frequency is applied to a conductive path (92) disposed on each of the accelerometers.

Abstract: A system (10) for controlling stabilization of a synchro (26), which is driven from a digital to synchro converter (12), which utilizes a current sensor (14) to detect the magnitude of the synchro current drive signal and through a compare and hold circuit (20) compares the magnitude of the current with a predetermined maximum current and if exceeded provides a signal to a logic control (22) which controls a current limiter (16), disposed in series with the conductors providing load current to synchro (26). Current limiter (16) operates in a non-current limiting mode, wherein load current is passed unhindered to synchro (26), and a current limiting mode wherein current limiting resistors are inserted in series with the conductors carrying drive current to synchro (26). When the commanded drive current exceeds the reference current, compare and hold circuit (20) initiates a signal to cause current limiter (16) to operate in the current limiting mode.

Abstract: A seamless frequency hopping system utilizes a programmable digital signal processor with interface circuitry in conjunction with a frequency hopping radio to incorporate the concepts of audio time compression, hop by hop automatic gain control and time repeating squelch to improve the sound of frequency hopped analog communication. Incoming uncompressed audio is first sliced into time segments that each correspond to one frequency hop. The uncompressed audio is then compressed to a certain percentage of its original length in time. A dead time as well as a pilot signal is added to the front of the audio. The processed audio signal is then sent to the radio where it is modulated and broadcast. A second radio receives the incoming signal and demodulates it to once again become an audio signal.

Abstract: A pneumatically dithered ring laser gyroscope features providing an oscillatory motion directly to a segment of the excited gas which serves as the laser photon source. Alternately switching ionizing potential between two cathodes in appropriately designed cavities establishes desired oscillatory gas velocities to effect emitted frequencies within the gyro, thereby permitting the detection of rotational rates below the "lock-in" rate of the undithered gyro.

Abstract: A transducer having compensation for a deflection due to an applied stress. The transducer includes a support ring (32) having a proof mass (34) cantilevered on a pair of flexures (38) between the magnets (26,28) of a stator in which the transducer is mounted. Deflection of the support ring due to an imbalanced applied force is compensated by either moving the pads (30) used to mount the support ring, moving the centroid of capacitance (42) of the proof mass, or by modifying the support ring to provide a pair of moment arms (152), each approach insuring that an axis of deflection (102,130) of the support ring is coaligned with the centroid of capacitance, thereby minimizing a bias error in the transducer output.