Abstract:
An optical fiber rotation sensor having an ordinary single mode fiber coil (10) with a depolarizer (10') in series therewith configured with component optical path lengths therein and birefringent axes relationships therein chosen with respect to the source autocorrelation. Amplitude related phase errors due to polarization mode coupling can be eliminated or reduced economically, and signal fading can be substantially prevented.
Abstract:
In a fiber optic gyroscope (10) having a pair of light waves counter-propagating in a fiber optic loop (44), a phase modulator (28) driven with a variable frequency and amplitude modulation signal on a line (32) so as to null any rotation induced optical phase shift, and using the difference between the drive frequency and the loop eigenfrequency as a measure of rotation rate, is provided with a calibration circuit (34) which determines the actual loop eigenfrequency while in rotation. A modulation signal is applied having an amplitude that causes the closed loop output frequency to equal the loop eigenfrequency independent of rotation rate. The amplitude is fine tuned by applying a phase dither and adjusting the amplitude until effects of the dither are minimized.
Abstract:
The present invention relates to a laser intensity monitor (10). Specifically the laser intensity monitor (10) uses a black chrome metallic, non-light transmissive mask (24) deposited on an optically transparent glass or sapphire window (16). The mask (24) has an aperture (100) therethrough. The mask (24) is positioned on the window (16) in such a manner that only the TEM00 mode of a counter-rotating laser beam is allowed to pass through the aperture (100) of the mask (24) and the window (16) to strike a photodetector (12).
Abstract:
A pressure transducer is provided which incoroporates numerous stress reducing characteristics. A pressure sensor is mounted to a ceramic plate (28) with a buffer plate therebetween to isolate the pressure sensor from stresses that could be transmitted through the ceramic plate. The ceramic plate (28) is necessary for the purpose of supporting a plurality of electronic components which comprise an amplification and compensation circuit. The ceramic plate (28) is separated from all parts of its housing (12) except a minimal central surface on a support boss (24) which provides the support for the pressure sensitive device (26). Electrical communication between conductive paths on the ceramic plate and terminals extending through the housing is provided by flexible electrical conductors. A cover is attached to the housing with snap acting contact which further isolate the housing from the cap. The housing (12) and cap (36) are constructed to support the housing in a noncontact association with an external device when feet on the cap are attached directly to the external device. This offset positioning of the housing with respect to the external component further isolates the housing from sources of external stress. The combined stress isolated techniques used in the present invention permit a pressure sensor to measure very low pressures with a high degree of sensitivity without introducing measurement problems that would otherwise be incumbent in this type of transducer because of externally caused stresses transmitted from external forces and originating in the transducer because of thermal stress.
Abstract:
An optical recording head for use with a magneto-optical recording device wherein a rhomfoid prism (20) is utilized having a single PBS coating (23) thereon and being totally internally reflective so that light from a source (30) will pass through the PBS coating once, be totally internally reflected, pass through the PBS coating a second time to form first and second beams, the first passing to the recording apparatus (92) and the second being reflected to pass to a detector (85) to monitor the intensity of the radiation. Light from the recording apparatus containing information is reflected back through the PBS coating to form third and fourth beams, the third being reflected to suitable detecting means (120) and the fourth being passed through the rhomboid prism where it is internally totally reflected and emerges to a detector (150) which is used for monitoring the focal position of the objective lens.
Abstract:
Described is a set of network organizations for allowing truly nonblocking messaging through very large switching systems. Crossbars and Clos organizations are employed. Return pathways are used to indicate blocked messages (due to busy output nodes or receiving nodes). On busy, a message may be rerouted through alternate paths through the network. A design for using busses for part of the network is also described.
Abstract:
A switching circuit having a plurality of switches (33, 33') each with a control region which can be energized to be caused to open or close, a controller having output devices (19, 20) therein which can selectively draw current from any in the controller to provide an energy output coupled to the control regions of the switches (33, 33'), and isolating devices (49-52) connecting the switches to the controller.
Abstract:
In a combustion system, fuel flow and fuel composition are sensed, and energy flow in the combustion system is determined based on the fuel flow and the fuel composition. Air flow of combustion air is also sensed. The fuel-to-air ratio in the combustion system is controlled as a function of the energy or oxygen demand flow determined and the air flow sensed.
Abstract:
A control system for providing individual blade control inputs to a four-bladed helicopter rotor. Limited authority series actuators located in a non-rotating portion of the helicopter are driven by a computer wich receives inputs from individual blade sensors and aircraft stabilization sensors, summed with cockpit control inputs, and the resultant motions transmitted to the rotor blades through a conventional swashplate wich drives four blades of the rotor and a translatable differential sleeve and summing linkage which drives only two blades. The differential sleeve is adapted for axially raising or lowering the swashplate. The combined motion of swashplate and differential sleeve is shown mathematically to result in individual blade control in pitch. Computed individual blade commands are converted from the rotating reference frame to cyclic, collective and differential blade pitch commands in the fixed reference frame through a coordinate transformation matrix.
Abstract:
Disclosed is a long life cathode for laser generators consisting of a cathode body having an electron emitting surface in which lasing gas molecules are embedded therein.