Abstract: A subranging A/D converter generates high and low voltages using first and second DACs. A voltage divider receives the high and low voltages to generate plural reference voltages. A bank of comparators compares the analog voltage which is to be converted to each of the reference voltages, and a clocked logic circuit generates an intermediate digital signal indicative of the analog value relative to the plural reference voltages. The intermediate signal is used to decrement the high voltage and increment the low voltage, so that the reference voltages produced by the voltage divider assume subrange values. The process is repeated for as many clock cycles as is required to converge the high and low voltages to equal the analog voltage.

Abstract: A composition suitable for forming polyalkylsilsesquioxane coatings is prepared by emulsion hydrolysis of one or more silanes in the presence of a nonvolatile, nonionic catalyst, a nonionic fluorochemical surfactant and sufficient water to only partially hydrolyze the silanes. The resulting stable composition will form the final resin upon exposure to atmospheric moisture. A novel resin, polymethyl/isobutylsilsesquioxane, is particularly suitable for such coatings.

Abstract: A coupler for extracting energy in the TE.sub.21 mode from a circular waveguide propagating energy in both the TE.sub.11 and TE.sub.21 modes, characterized in that an annular iris on the inner circumference of the waveguide and a longitudinally stepped transition portion of the waveguide define therebetween a TE.sub.21 mode resonant cavity which is coupled via a narrow axially extending rectangular slot contained in the wall portion of the waveguide which defines the cavity. At least one external resonant chamber may be provided on the waveguide through which the TE.sub.21 mode energy is extracted and transmitted to a detector thereof via the slot, which chamber cooperates with the resonant cavity to define a multiple resonant filter for improving the matching to the TE.sub.21 mode while reducing the perturbation to the TE.sub.11 mode.

Abstract: An end effector suitable for manipulating articles such as mail flats is disclosed. This end effector has parallel reciprocating arms having suction cups for gripping the article to be manipulated and mechanical grippers mounted on the arms outboard of the suction cups. These mechanical grippers may be actuated to provide a mechanical grip on a manipulated article in addition to the suction grip.

Abstract: Cost and weight of a heat transfer structure for a space vehicle can be reduced by an arrangement of redundant channels for the flow of coolant to heat radiating panels, micrometeroid resisting bumpers located adjacent the channels for preventing penetration by all but the most energetic micrometeroids, and a sensing and control arrangement for sensing the penetration of a coolant channel for shutting off that channel to prevent loss of coolant.

Abstract: A high data rate optical network data communication system includes a receiver including a photodiode detector, a data slicer and a data decision circuit. A clock recovery arrangement includes an impulse generator coupled to the data slicer to generate impulse signals. The impulse generator includes a high speed ECL NOR gate driven by mutually out-of-phase and relatively delayed data. The impulse signals are applied to ring a coaxial cavity by way of a resistor and an input magnetic coupling loop. The coupling loop allows the cavity to achieve high Q so it will oscillate for a relatively long time, and also provides a path by which bias is applied to the output of the NOR gate to fulfill ECL biasing requirements. The cavity Q is maintained high by coupling signals from the cavity by way of a second magnetic coupling loop. The oscillations are applied by way of a limiter to the data decision circuit.

Abstract: An overdrive control for a GaAs FET power amplifier is provided by a PIN diode attenuator positioned at the input of the FET amplifier where the amount of attenuation is controlled by a control signal derived from the gate current of the following FET amplifier.

Abstract: An unbalanced quarternary phase-shift keying modulator provides relatively higher signal power for one of two signal information channels. The carrier to be modulated is split into two equal-amplitude, equal-phase portions, each of which is applied to a biphase modulator. Each of the information signals is also applied to one of the biphase modulators, for producing two equal-amplitude, phase modulated carriers, each biphase modulated by one of the information signals. The modulated carriers are applied to the ports of a quadrature hybrid coupler which is other than a 3 dB (equal-amplitude) coupler. In one embodiment, the coupler is a 7 dB coupler. The modulated carrier applied to the through port of the coupler appears with reference amplitude and phase at the output of the hybrid. The modulated carrier applied to the other or coupled port appears at the output with relatively reduced amplitude and a relative phase shift. In one embodiment, the phase shift is 90.degree..

Abstract: A novel material is disclosed which is the reaction product of acrylic acid and a novoloid fiber. The material has excellent ablative and flame resistant properties.

Abstract: A set of magnetically responsive vanes are secured for rotation about their mass center of gravity in a given angular spacing. The vanes have corresponding magnetic field producing coils which are in a different angular spacing such that one coil and vane is aligned and a second coil and vane are misaligned. An electrical switch is coupled to the vanes for operation in response to rotation of the vanes. A current applied to one coil aligns its vane thereto and closes the switch. The closed switch applies a load current to a second coil whose vane is misaligned. When an overcurrent occurs, the corresponding resulting field aligns its vane and opens the switch. An off current applied to a coil can align a corresponding vane to also open the switch. The switch and actuator are dynamically balanced so that moments produced by shock and vibration do not operate the actuator vanes or switch.

Abstract: A nutation damping control for a dual-spin satellite is provided by tilting the axis of the rotor relative to the normal spin axis of the satellite and back a half nutation period later. The tilting is in the direction of the angular momentum vector component that is transverse to the rotor's spin axis.

Abstract: A balun comprises a one-to-two, equal-power, matched power divider having branch transmission lines whose lengths differ by 1/2 wavelength at a design frequency. The shorter of these two branch transmission lines has two 1/4 wavelength long, shorted stub transmission lines branching therefrom 1/4 wavelength apart.

Abstract: A power conversion system is constructed of a plurality of identical Stirling engine modules paired off in opposed, aligned relation with their respective expansion spaces in juxtaposition. Two engine module pairs are arranged in a common plane and in mutually perpendicular relation to create a module group, with plural such module groups stacked together to provide an expanded, self-balanced system with all the modules sharing a common, centrally located thermal energy source. Each module includes a pair of compression positions operating on a common axis intersecting the displacer cylinder axis at right angles. Heat exchangers, either tubes or heat pipes, are disposed within the expansion space to transfer heat from the source to the working fluid therein, thus providing a more idealized Stirling engine cycle.

Abstract: The present invention provides three embodiments of circuitry, responsive to the application of an energizing pulse to the high pressure tube of a hybrid laser, for de-energizing the normally continuously energized low-pressure tube of the hybrid laser for only a given time interval which is longer than the duration of the high-energy pulse of coherent wave energy generated by the high pressure tube when energized. This solves a prior-art problem of sporadic spike emissions by the low-pressure tube during the time interval in which echoes from objects of interest are being received by a LIDAR employing a hybrid laser transmitter portion.

Abstract: An electrically regeneratable fuel cell is disclosed which has positive electrodes comprised of an alloy of about 50 to 55 percent by weight of silver and about 50 to 45 percent by weight of indium. The fuel cell of this invention is chargeable to a higher voltage at a lower pressure, has a substantially higher capacity, lower internal resistance and is lighter in weight than comparable conventional electrically regeneratable fuel cells.

Abstract: A support fixture for a printed circuit board connector having L-shaped wire wrapping pins attached to a printed circuit board includes a plurality of L-shaped elements, each for placement in the L-shaped space defined by adjacent arrays of pins, connector body and printed circuit board. An outer L-shaped structure is juxtaposed with the pins at their bends and with the elements to preclude motion of the pins at their bends in response to wire wrapping forces on the ends of the pins protruding from the printed circuit board.

Abstract: An apparatus for testing the crosspoints of an RF switching matrix injects a test signal having the characteristics of noise into the matrix. The test signal recovered from the matrix is mixed with a frequency-swept signal and the difference signal is applied to a bandpass filter. The filter provides a window through which all of the frequency-shifted components of the recovered signal pass during the period of the frequency-swept signal. The total energy of the components in the window is continually monitored during the sweep period. A comb generator provides the test signal having a multiplicity of substantially equal amplitude components, uniformly spaced over a selected frequency spectrum. The frequency-swept signal is provided by a VCO having a sawtooth waveform input voltage. The amplitudes of the test signal components are sufficiently low that if coupling occurs between the test signal and a configured external antenna, the resulting transmission is virtually indistinguishable from noise.

Abstract: Thermoelectric elements of both P-type and N-type lead tellurides having unique characteristics including, particularly in the case of the P-type, a figure-of-merit 90% above that of the best commercial P-type element, are produced by a new process involving as key steps chill casting, cold pressing and sintering to 85-90% theoretical density under protective atmosphere.

Abstract: A burst mode fiber optic or light-wave communication system uses as a transmitter a light emitting device requiring drive current to produce a light output. The characteristics of the light emitting device change with time, so the drive current must be periodically adjusted. In a high speed burst data system, the magnitude of the light output and the new value of drive current cannot be determined until a time well after the beginning of the burst, or possibly after the burst has ended. If the drive current is adjusted to a new value during burst transmission, the change in light output may be interpreted by a receiver as a data transition, which may result in data errors. The change in the control signal which controls the magnitude of the drive signal is delayed until a time between data bursts, whereby the drive current magnitude remains constant during any burst transmission.

Abstract: Thermoelectric elements of both P-type and N-type lead tellurides having unique characteristics including, particularly in the case of the P-type, a figure-of-merit 90% above that of the best commercial P-type element, are produced by a new process, involving as key steps chill casting, cold pressing and sintering to 85-90% theoretical density under protective atmosphere.