Abstract: In a servoactuator system for an aircraft, a strapdown series servoactuator having an external linkage assembly is coupled between the pilot's control stick and a control surface member. The external linkage assembly includes a differential link and servo link having specially tapered stop surfaces adapted to be varied in dimensions to accommodate a wide variety of installations, which stop surfaces cooperate with fixed stops on the servoactuator housing whereby to provide a variety of pilot authority limits and series servo authority limits depending upon particular installation requirements.

Abstract: In a geothermal production well, oil well or gas well, a thermally energized packer cup having a tapered elastomer body and a reinforcing element fabricated from a shape memory alloy seals the well casing when the packer cup is heated to the transformation temperature of the shape memory alloy.

Abstract: A fin line apparatus, within a rectangular waveguide, for detecting R.F. signals utilizes metallic film conductors, disposed on both surfaces of a planar dielectric centered in the waveguide parallel to its sidewalls, for forming aligned channels, a first of which couples R.F. signals to a diode which provides rectified signals to a metallic film filter disposed in a gap in a conductor which opens into the first channel.

Abstract: In a flapper nozzle actuator system a radial outward flow turbine like flapper is used as the flapper. The angular velocity of the turboflapper is used to lift the turboflapper off a backplate towards a nozzle. The amount of lift off the backplate and hence nozzle outlet area is a function of the angular velocity of the turboflapper. An adjustable opposing torque on the turboflapper controls the angular velocity of the turboflapper and thus controls the flow rate.

Abstract: A power supply system that utilizes a plurality of inverter power supplies connect in common to drive a common load with control circuitry for forcing the power supplies to share the load equally is described. Control circuitry associated with each inverter power supply senses the current level provided to the load and compares to the average current provided by all other power supplies in the system. The control circuitry includes circuitry for controlling the pulse width modulator circuitry in response to the sensed condition that the power supply is supplying more than its equal share of the load and causes it to adjust the duty cycle of power switches in the power supply downward to reduce the output current level.

Abstract: A beam forming network comprising multi-deck circuitry with a plurality of levels within each deck formed by asymmetric striplines having a multiplicity of inner conductor levels. Interlevel coupling is accomplished with 3 dB couplers which power split signals incident thereto between transmission line levels and 0 dB interlevel couplers which transfer signals from one level to another without significant attenuation.

Abstract: A high frequency inverter power supply having isolation between the drive circuitry and the Power Switching device and utilizing a Field Effect Transistor as the Power Switching device is described. Circuitry for rapidly charging the gate capacitance of the Field Effect Transistor for enhancing the rate of its switching to the conductive state and for rapidly discharging the gate capacitance for enhancing the rate of its switching to the non-conductive state is shown.

Abstract: A sonar array wherein the capacitance associated with the hydrophones of the array are utilized as shunt elements in an artificial transmission line in order to form an acoustic beam. Series inductance elements to the transmission line are variable with d.c. current flowing through coils wound about a magnetic core about which coils forming the series inductance of the line are also wound, thus permitting the sonar beam to be steered to any desired position.

Abstract: An incoming signal is tested for the presence or onset of a frequency shift keyed (FSK) signal which alternates at a known rate between two unknown frequencies separated by a known frequency shift. The incoming signal is time delayed an odd multiple of the keying period and the delayed signal is multiplied by the incoming signal to produce sum and difference frequencies when the FSK signal is present. The difference frequency is selected by filtration, demodulated and integrated to produce a useable detector signal. The detector signal is compared with a threshold signal which is generated to discriminate between the FSK signal and other unwanted signals or noise in the communication channel.

Abstract: A thin film magnetic read/write transducer has a substrate of magnetic material forming a pair of disparate pole pieces. Arranged adjacent a movable magnetic medium, the disparate pole pieces are constructed so that the leading pole piece has a greater distal surface area than the trailing pole piece. In an alternative arrangement the leading pole piece distal surface is disposed a greater distance from the medium than the trailing pole piece. In yet another arrangement the trailing pole piece distal surface is disposed at an acute angle to the medium, and the leading pole piece surface may be at a lesser angle or parallel to the medium. The disparate pole pieces, so constructed and arranged, introduce compensating non-linearities to the writing magnetic field to substantially counteract the non-linear properties of the medium and of the recording process.

Abstract: A fiber optic transducer is provided by cutting and polishing the ends of two optical fibers, having equal indexes of refraction, at angles with respect to their axis such that all light signals propagating within the optical fibers are incident to the end face at angles that are greater than the critical angle defined for an interface between a medium with an index of refraction equal to the index of refraction equal to that of an intervening medium between the two fibers. The two end faces so cut are positioned to be in a parallel relationship, a distance apart that is less than the wavelength of the light propagating within the input fibers. Variations of this distance with the pressure changes caused by the acoustic environment produces variations in the optical signal energy coupled from the input optical fiber to the output optical fiber, thus creating an amplitude modulated light beam that propagates in the output optical fiber.

Abstract: A Josephson tunnel junction device having niobium nitride superconductive electrodes includes a polycrystalline semiconductor tunneling barrier therebetween comprised of silicon, germanium, or an alloy thereof preferably deposited on the lower superconductive electrodes by vapor deposition. The barrier thickness of the junction is controlled by precision doping of the semiconductor material. The active junction is defined after the interfaces between the barrier material and the two superconductor lines are formed, retaining those active interfaces in fully unpolluted character.

Abstract: A voltage converter of the transformer type which incorporates at least one switching transistor coupled to control the application of current to the transformer primary and circuitry for switching the transistor off in response to the current drawn through the primary winding and the level of the input line voltage. Overcurrent shutdown may thus be tailored to approximate constant power dissipation within the voltage converter.

Abstract: In a patterned screen color cathode ray tube (CRT) display, for example, a shadow-mask type color CRT, particularly for use under a wide range of ambient light conditions, such as an aircraft cockpit, incompatibilities between the screen pattern character, the type of writing (such as stroke and raster), and the display linewidth, may result in stroke written lines which appear as a twisted fiber rope and in raster written areas which appear wavy or watery; that is, a moire appearance. Both of these effects vary in accordance with the required display brightness over the ambient light range due to variations in beam or linewidth with corresponding variations in the required cathode drive voltages.

Abstract: A detector for determining whether the time duration between a positive and a negative peak of a waveform is greater or less than a predetermined time interval comprises a delay line for delaying the waveform by the predetermined time interval. A peak detector of a first polarity for detecting the first occurring peak of the waveform is responsive to the delayed waveform to provide a signal upon the occurrence of the first occurring peak thereof. A peak detector of a second polarity for detecting the second occurring peak of the waveform is responsive to the undelayed waveform for providing a signal upon the occurrence of the second occurring peak thereof. A time sequence comparator provides a first output indication when the signal from the first peak detector occurs prior to the signal from the second peak detector and a second output indication when the signal from the second peak detector occurs prior to the signal from the first peak detector.

Abstract: The digital-to-analog converter comprises an R-2R ladder network with bit controlled current steering switches connecting the legs of the ladder network to first and second current buses. First and second current-to-voltage converters are connected to the current buses respectively, the second current-to-voltage converter being connected through a switch to the input of the first current-to-voltage converter. A uni-polar/bi-polar control signal renders the switch conductive or non-conductive in accordance with the data format desired. The digital-to-analog converter is also utilized in a successive approximation analog-to-digital converter.

Abstract: In a flow meter of the traveling wave type having a flexible undulating membrane, velocity detecting means is utilized to determine the velocity of propagation of the traveling wave associated with the undulating flexible membrane between at least two known locations on the flexible membrane. The velocity of propagation is proportional to the volumetric flow rate of fluid through the flow meter.

Abstract: A control circuit for driving solenoids protects these devices from failure due to overheating caused by frequent on-off cycling. Control signals are passed through logic gates. A timer responds to the termination of a control pulse and disables the logic gate that passes signals to the load for a predetermined time, thus restricting the minimum off time of the solenoid. Minimum on time or maximum on or off times are not affected.

Abstract: A separated substrate acoustic wave device having an active piezoelectric substrate and a separate base substrate. Input and output transducers are mounted upon the base substrate. The active substrate, which includes grooved-array reflectors in the case of resonators, is mounted opposite the base substrate so that it does not contact the transducer electrodes and further so that electric fringing fields generated in the transducers will induce an acoustic wave due to the piezoelectric effect in the active substrate. Similarly, acoustic waves propagating in the active piezoelectric substrate will have an associated electric field which induces an electrical signal in the transducer permitting detection of the acoustic waves propagating in the active substrate.

Abstract: In a geothermal energy conversion system having a boiler, a liquid trap, and a turbine driven pumping unit, a thermosyphon boiler is disposed between the liquid trap and the turbine driven pump. The thermosyphon boiler evaporates the liquid collected in the liquid trap and then superheats the evaporated liquid and steam emitted from the boiler such that the steam directed into the turbine driven pumping unit is of extremely high quality.