Abstract: Gain peaking and attenuation of audio signals above the peak gain frequency are provided in an audio frequency equalization preamplifier that includes an operational amplifier having a feedback network including first and second resistors and a feedback capacitor connected between the output and the second feedback resistor. Two or three low pass RC filter sections are connected between the audio signal source and the noninverting input of the operational amplifier with a circuit connecting a capacitor of the second RC section from the noninverting input to a node between the second feedback resistor and the feedback capacitor.

Abstract: To increase the effectivity of warnings and to decrease nuisance warnings in a ground proximity warning system having several modes of operation, the switching from one mode to another is done as a function of radio altitude and time. In addition, in a ground proximity warning system where a warning signal is generated in accordance with a predetermined relationship between flight parameters, one or more of these parameters can be varied as a function of radio altitude and time in order to, for example, increase the altitude above ground as a function of radio altitude and time from take-off that a terrain clearance warning is generated or to decrease as a function of radio altitude and time, the radio altitude below which a negative climb after take-off warning is generated.

Abstract: Automatic selection of a directional antenna providing the best television reception is provided for in an antenna control circuit that includes a circuit for automatically sampling the video output for each directional antenna and connecting the directional antenna that produces the strongest video signal to the receiver. The antenna control circuit includes a timer circuit that responds to the horizontal and vertical synchronizing pulses of the receiver to control the duration and timing of the sampling.

Abstract: The present invention is directed to a simplified viscosity compensating circuit which utilizes a viscosity sensitive capillary and a flow restriction means in series therewith to regulate the pressure at a particular point in a control circuit in response to a change in viscosity of the control fluid. Such viscosity compensation in the circuit is utilized to either maintain a uniform pressure at the circuit output or off-set an adverse condition caused by a change in viscosity of the control fluid.

Abstract: In order to provide a magnetic tape recorder where the magnetic tape and tape reels are driven by a drive belt with the capability of operating in temperature extremes, the drive belt is composed of silicone rubber that has been cured with a peroxide curing agent.

Abstract: This invention relates to a fully modulatable centrifugal pump capable of handling a fluid containing solid contaminant particles and minimizing the temperature rise of the pumped fluid. The pump is of the type that includes an impeller to propel the fluid through a radial outlet to a diffuser which includes a plurality of diffuser passages. The improvement is comprised of the following cooperative combination which includes rotatably mounted valve elements passing, in part, through the diffuser and across the diffuser passages. Each of the valve elements have a port therethrough to variably selectively allow fluid passage therethrough upon rotation of the valve element. A driving arrangement is coupled to each of the valve elements to thereby affect a yieldable rotation of the valve elements in one direction to progressively reduce the opening of the valve element port to the diffuser passage.

Abstract: A simple compact actuator mechanism for converting pivoting motion to planar motion is disclosed. The mechanism comprises a housing supporting a handle shaft for pivoting motion and supporting a disc for planar sliding motion. The disc is connected to the shaft at a point spaced from the pivot point whereby pivoting of the shaft causes translation of the disc.

Abstract: The present invention relates to an improved blade pitch control mechanism for an air driven turbine blade mounted for rotation in a hub assembly. The control mechanism includes a drive member mounted for reciprocation along a central axis of the hub assembly. The drive member has a control member secured to one end and a seat member at the other end. The blade has operatively coupled thereto, a centrifugally responsive means which includes a pin in mating engagement with the control member. A spring is positioned between the hub assembly and the control member to thereby cause the blade to assume a coarse or high pitch position when the blade and hub assembly are in storage. A slide member is mounted on a portion of the hub assembly for reciprocation along the central axis. A spring is positioned between the seat member and the slide member. A flyweight is supported on the hub assembly and engages the slide member.

Abstract: A capacitive differential pressure transducer for sensing the difference in pressure between at least two fluids includes first and second halves of a housing separated by a diaphragm which acts as a common capacitive plate to the capacitive differential pressure transducer with each housing half being identical and containing an interior chamber which is filled with a force transmitting fluid, a sensing capacitive plate located within the chamber and cooperating with the common capacitive plate, a fastening mechanism for holding the sensing capacitive plate tight against its housing half, sealing devices for sealing in the force transmitting fluid and terminals for connecting the common capacitive plate and the sensing capacitive plate to a sensing circuit.

Abstract: The present invention is directed to a simplified one-piece sleeve used in a face seal assembly to maintain elements of the face seal in abutting relationship from the time of assembly in a clean room environment until final positioning of the seal elements within a shaft housing environment to insure both cleanliness and concentricity of the face seal elements.

Abstract: A vehicle propulsion system is provided with an auxiliary hydraulic drive having a variable displacement motor connected to ground engaging wheels by a clutch. A multiple position control has a first position which causes clutch engagement and positions a motor displacement member in a position which permits fluid drive of the motor. The control has a second position which causes clutch disengagement and positions the motor displacement member in a zero displacement condition which prevents fluid drive of the motor. Preferably the control is responsive to motor output speed and reduces motor displacement as speed increases.

Abstract: To provide for accurate determination of azimuth in a borehole survey apparatus, a downhole probe is provided with two or more sections connected by torsionally rigid, flexible joint assemblies with provisions for generating signals that represent the relative inclination and azimuth of one probe section from another. These signals are combined with inclination signals obtained from a set of accelerometers in one of the probe sections in a signal processing unit to generate signals that represent the direction and depth of the borehole.

Abstract: This invention relates to a method and a system including apparatus for submerging, entraining, melting and circulating aluminum scrap in a molten metal media, which scrap is comprised of pieces not capable of self-submergence. The apparatus of the system includes means to introduce a supply of scrap into an open bay that has heated molten metal drawn from an entry point below the surface of the molten metal by the action of a molten metal scrap entrainment circulator submerged beneath the surface of the molten metal at a point beneath the entry point of the heated molten metal. The circulator continuously draws the heated molten metal including the scrap into the circulator wherein the scrap is completely entrained in the molten metal and delivered into a molten metal circulation path that delivers the scrap metal entrained in the molten metal for subsequent heating further melting and recirculation to the circulator.

Abstract: This invention relates to a pulse width modulated inverter circuit having an output signal with reduced harmonic content. The inverter circuit includes a first circuit that provides a filtered fundamental pulse width modulated signal. A second circuit is electrically coupled to the first circuit to receive the signal and sum therewith a controlled signal and the filtered fundamental pulse width modulated signal. The second circuit thereby providing the output signal with reduced harmonic content.

Abstract: This invention relates to a panel air chiller for use with a portable food storage unit. The panel air chiller includes in combination first and second spaced apart parallel panels that have thermal insulation disposed between and in contact with the panels. The thermal insulation material has formed therein at least a first and a second chamber between the panels thereby establishing passageways between the panels and through the thermal insulation material. Located in the first chamber is a means to extract heat from air passing thereover to thereby cool the air. At least one return air opening is provided through one of the panels to communicate with the portable storage unit. A fan is coupled to the space between the panels and to the first chamber to thereby draw air through the return air opening coupled to the portable storage unit.

Abstract: For use on a vehicle having a split torque transmission, the split torque transmission including first and second throughputs and a summing junction connected to the first and second throughputs and having a transmission output dependent upon the first and second throughputs, each throughput having an input connected to an output of the engine of the vehicle, the system including a sensor adapted to sense the output of the engine, and a controller connected to the sensor and adapted to control the second throughput dependent upon the engine output, the second throughput being controlled from a negative value cancelling the first throughput to a positive value so that the transmission output is varied from idle to a predetermined value.

Abstract: This invention relates to a drive circuit coupled to electrical devices, which may be semiconductors, connected in parallel in a circuit network. The electrical devices have distinct total on-time periods when they are simultaneously energized. The circuit network has a source of power coupled through the parallel connected devices to a load. The drive circuit includes a signal source coupled respectively through a time adjustable circuit to a first electrical device and to a second electrical device. The time adjustable circuit is adjusted such that the total on-time of the first electrical device matches the total on-time of the second electrical device to thereby ensure equal power at all times through the electrical devices to the load. The invention allows a number of parallel devices to act as a single switch.

Abstract: This invention relates to a DC powered emergency heating system control circuit for use in combination with a gas furnace that includes an AC power supply for a thermostat to control a normally operated AC powered automatic gas valve, which gas valve provides gas for burning in a plenum chamber. The control circuit includes an auxiliary fan and circuits responsive to the interruption of AC power to provide in a repetitive sequence, DC power pulses of one polarity to the automatic gas valve, followed by energization of the auxiliary fan, followed by the application of DC power of an opposite polarity to the gas valve. This repetitive sequence thereby ensures alternate periods of convection and auxiliary fan induced forced air heating while simultaneously protecting the normally AC powered gas valve from the deleterious magnetism effect brought on by the continuous emergency DC powered operation of the gas valve.

Abstract: A frequency detector for detecting the frequency of vibration of an apparatus is disclosed having a first vibration sensor for providing a first output having a first frequency response to the vibration, a second vibration sensor for providing a second output having a second frequency response to the vibration where the first and second frequency responses envelope the desired frequency of vibration for the apparatus, a difference sensor connected to the first and second vibration sensors for providing a third output dependent upon the difference between the first and second outputs, and a load which is responsive to the third output.

Abstract: A tape cassette particularly adapted for use with a dual capstan magnetic tape deck that does not utilize pinch rollers, includes a pair of capstan actuators that respond to a central loading knob which serves to move the tape away from the capstans when the cassette is loaded or unloaded into the tape deck. In addition, the cassette includes a pair of tape guide actuators that respond to the loading knob by rotating and forcing the tape away from the magnetic head and tape guide pins of the tape deck during the loading or unloading operation. This single knob controls both the capstan actuators and the tape guide actuators. The capstans and reels are arranged such that a large angle of wrap, 165.degree. or more, around the capstans is provided in order to effectively drive the tape without the need for pinch rollers.