Abstract: A device for converting a set of electronic signals that represent an image into a coherent image includes a two-dimensional array of asymmetric Fabry-Perot (ASFP), quantum-well-based optical modulators connected on a pixel-by-pixel basis to a two-dimensional array of drive circuits located on an integrated circuit. Electronic signals received by the integrated circuit cause the pixel drive circuits to change a bias voltage applied across the optical modulator section and, thereby, change the optical properties of the optical modulator section of the device. The two-dimensional array can be used to impart intensity-only, phase-only, or phase-and-intensity variations onto a beam of coherent laser light incident on the array. This coherent image can be used with other optical elements to form optical processing machines and optical storage devices.

Abstract: An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

Abstract: A method and apparatus for identifying a remote target includes a transmitter for transmitting pulses of energy toward the target for generating echo signals, and a receiver for receiving the echo signals, and for generating received signals representing the target, noise and clutter. The received signals are applied through a plurality of cascaded channels, each including a Doppler filter cascaded with a multiplier, each also including range sidelobe suppression, for, in each of the cascaded channels, narrowband filtering the signals passing therethrough about a controllable center frequency, and for, if necessary, converting the signals passing therethrough to baseband, for thereby applying one of a plurality of Doppler filtered baseband signals to the input of each of the range sidelobe suppressors of each of the cascaded channels. The power of the Doppler filtered baseband signals in each range bin is evaluated for determining the frequency at which the spectral density is greatest.

Abstract: The electrical length of a strip transmission line structure is adjusted by adding conductive projections from the ground planar conductors which extend in depth toward the strip conductor and in length along the strip conductor. These projections may preferably be formed by inward deformation of the ground planes at the desired locations. In strip transmission lines having the strip conductor positioned between two ground planes, projections are preferably added in aligned pairs with each ground plane providing one of the projections of the pair.

Abstract: A hinge includes a first clevis (30), defining a vee-block support (12) and a first limiter surface (44, 46, 48). A cylindrical hinge shaft is supported by the vee-block (12). A second clevis (140) is affixed to the shaft, whereby the second clevis may rotate in response to torques. The second clevis has a limiter surface (148) which coacts with the first limiter to limit rotation of the shaft and second clevis past the deployed state. The second clevis (140) has a cam follower (158) at a predetermined distance from the axis of rotation (2). A cam (100, 104) affixed to the first clevis (30) rotates about a cam axis (3'). The deployed-state engagement between the cam and the follower snugs one end of the shaft into the vee-block, while the rotation limiters snug the other end. A rotational driver (50, 54, 70, 75, 90, 110) urges the cam (100, 104) to rotate in a direction which tends to move the second clevis (140) from the stowed state toward the deployed state.

Abstract: A passive damping mechanism for a panel member in which a bonding layer is disposed on each side of the panel, a damping layer is disposed on each of the two bonding layers, and a constraining layer is disposed on each of the two damping layers. Each of the above-mentioned layers is coextensive with the respective panel surfaces to which it is attached. The bonding layers are preferably made of an aramid fiber material. The damping layers are preferably made of a viscoelastic material. The constraining layers are preferably made of an aluminum-graphite metal matrix composite material. In addition, the coefficient of thermal expansion of each bonding layer should match well with that of each constraining layer.

Abstract: An active array antenna, which may be used for radar, includes antenna elements (antelements) supported in a two-dimensional array. The fronts of the elements are protected by a cover. In order to allow easy repair, each column of antelements is associated with a slide-in carrier which simultaneously mates with all antelements of a column. Each carrier has a transmit-receive (TR) module for each antelement with which it mates, and a column beamformer. Each carrier also has logic modules and power supplies for the TR modules. The total width of each slide-in carrier with its TR modules, beamformer, logic and power supplies, is less than or equal to the column-to-column spacing. Each carrier can be slid out from the rear to expose all the active components for each column of antelements, so maintenance can be performed without environmental exposure.

Abstract: A spacecraft (10) includes N paralleled power converters (24a, 24b . . . ) for producing current pulses in response to converter synchronizing pulses. The current pulses are integrated (28) to produce an operating direct voltage. The synchronizing pulses are produced in a recurrent cycle by a synchronizer (30). The synchronizer includes a voltage divider (320) with equal series-connected elements (324a, 324b . . . ), each of which is paralleled by a shorting switch (330a, 330b . . . ). A sawtooth signal generator (310) produces a sawtooth signal (312), which is applied in common to each of a plurality of comparators (332a, 332b . . . ). The voltage divider (320) is connected across a reference voltage (318), to produce a plurality of reference voltages at the taps (328a, 328b). Each comparator (332) compares the sawtooth ramp (314) with one of the reference voltages, so that the comparators trigger in sequence as the ramp rises. The comparators trigger at times corresponding to equal phase increments of 360.

Abstract: A Fabry-Perot etalon (310) has a cavity (12) occupied by an electric-field variable index of refraction material (22). The cavity is flanked by a pair of parallel mirrors (14), at least one of which is partially reflecting. At least one of the supporting substrates (18l) has deposited thereon a light polarizing field electrode (316l) which includes a plurality of mutually parallel, spaced apart electrical conductors (392) which define gaps (394). The electrical conductors are mutually interconnected by bus conductors (390), and may be connected by lead conductors (37) to an external voltage source, for generating the desired electric field across the cavity.

Abstract: A capacitance multiplier/regulator (FIG. 1) stores charge at high voltage across a capacitor (22,32), and capacitance-multiplies current to a load (100) by step-down transformers (26,36), controlled switches (24,34), and rectifiers (28,38). The switch pairs (24a,24b;34a,34b) each switch in antiphase, but the switching phase between the pairs is controlled (FIG. 5) in a feedback manner to controllably generate a voltage across a transformer primary winding (14.sub.p), which couples a feedback-controlled alternating voltage across secondary winding (14.sub.s). The alternating voltage is added to the unregulated voltage by a rectifier (18,20), so the bus voltage is controllably greater than the unregulated input voltage. The feedback controls either the bus voltage or the load voltage. Stress on the switches is reduced by preventing capacitor recharge during a load pulse.

Abstract: An optical demultiplexer includes an electrooptic modulator (410) which modulates a beam of light (418) in response to frequency-multiplexed radio-frequency (RF) information signals, to produce diverging beamlets of light (420). The diverging beamlets are separated by a spatial separator arrangement (426), and each beamlet (420), including the information of its RF carrier, is coupled to a separate optical detector (428). The detector (428) can extract amplitude modulation from the signal. In order to reconstruct the RF signal as well as the amplitude modulator, an optical "local oscillator" signal (OLO) is coupled to each detector together with its information signal. Signal loss due to vibration or misalignment is avoided, and heterodyne mixing efficiency is maximized in an embodiment of the invention, by propagating the OLO and information signals through a single-mode optical fiber to the detector.

Abstract: A method for making a pressure tank includes procuring a metallic feed pipe (12) with a substantially cylindrical outer surface (312), a bore (21), and, at an attachment end thereof, an annular ring (350) protruding from the cylindrical outer surface. A dissolvable mandrel (410) in the shape of the desired tank or pressure vessel is made. The mandrel includes a neck portion (412, 414) dimensioned to fit within the bore of the feed pipe. If necessary, the outer surface of the mandrel is rendered electrically conductive, as for example by metal sputtering or evaporation, or by electroless deposition. A thin layer (328) of ductile metal is then electrolytically deposited over the outer surface of the mandrel, extending onto the outer surface of the feed pipe in the pipe-to-tank coupling region, closely fitting over the annular ring, to thereby form a tank liner. A composite reinforcing shell (322) is formed around the liner, and extending over the liner in the coupling region.

Abstract: A radar transmits dispersed pulses in which the subpulses are modulated by first and second mutually complementary code sequences, the autocorrelation functions of which are selected so that, in the sum of their autocorrelation functions, the main range lobes add, and the range sidelobes cancel. The received pulses with their Doppler sidebands are applied to a plurality of channels, each of which (except one) contains a mixer-oscillator combination that removes a specific Doppler phase shift along the range dimension at a different channel frequency. One channel has no mixer-oscillator because it is centered at a zero channel frequency. Within each channel, the received signals modulated by the first and second codes are matched-filtered by filters matched to the first and second codes, respectively, to produce first and second time-compressed pulses, each including (a) a main lobe representing the target range, and (b) undesirable range sidelobes.

Abstract: A data receiver receives differential phase-shift keyed (DPSK) signals, and filters the signal by a process including frequency conversion, under the control of an estimated carrier frequency (f.sub.re), to produce a filtered output signal which is applied to a DPSK demodulator. The filtering compensates for the Doppler frequency errors, and reduces the phase error. The estimated frequency is determined by second and third controllable filters, which filter the DPSK carrier signal at frequencies above and below the estimated carrier frequency by an offset frequency which depends on the data rate. A first frequency error estimate is made in a processor coupled to the second and third filters, from the ratio of the amplitudes of the first and second filter output signals. A second-order tracking loop is coupled to the processor for averaging the frequency error estimate over a predetermined number of bits, to generate the estimate of the carrier frequency.

Abstract: A method for making a storage tank with an integral vane starts with a feed pipe. A thin, flat vane has a shape which defines an inner and outer curve extending between attachment and second ends. The outer curve of the vane is dimensioned to lie just within the inner periphery of the tank, spaced therefrom by a particular gap. The attachment end of the vane is affixed to a first part of a coupling region of the feed pipe, with the pipe axis lying in the plane of the vane. The vane-pipe combination is placed in the cavity of a mold having the desired interior shape of the tank, with the edge of the outer curve of the vane spaces away from the wall of the mold by the desired gap. A dissolvable, hardenable liquid is injected into the mold and hardened. The mold is removed, leaving a soluble mandrel in the shape of the cavity of the tank. A copper coating is applied to the mandrel and the pipe, to form a metal liner including a neck extending over the feed pipe.

Abstract: A Fabry-Perot etalon 10 is located in the light path 30 between a light sourcesinks 40 and 44. The etalon is polarization insensitive, and its optical path length and transmission wavelength(s) is controlled by a bias source 60. When light at the desired wavelength is propagating from source 40, the bias is set to establish transmission through the etalon at that wavelength, whereupon the light propagates to the sink 44, and the switch is transmissive. By contrast, if the switch is to be nontransmissive, the bias sets the transmission wavelengths of the etalon on either side of the wavelength produced by source 40, whereupon the light from source 40 is reflected by the etalon, and does not reach sink 44. In a second embodiment, a third sourcesink 48 is coupled in a second light path 330a, for being coupled to the first sourcesink 40 when the etalon is set for reflection, to thereby form a single-pole, double-throw switch.

Abstract: An MSK receiver includes a downconverter for downconverting the received MSK signals. The phase drift or phase error per bit of the message preamble is determined. The reference carriers are generated, and the phase of the reference signals is adjusted during message demodulation under the control of the estimated rate of phase change across the preamble portion. In accordance with another aspect of the invention, the downconverted MSK signal burst is digitized and the digitized burst signal is stored in memory, following which it is read repeatedly so that bit timing, start-of-message timing, carrier phase, and carrier drift processing may be performed in a desired sequence, using all the available information for more accurate demodulation. According to a yet further aspect of the invention, a second order tracking loop is used to adjust the phase of the demodulation reference signals.

Abstract: A modulator or demodulator has a transparent nonlinear dielectric material (crystal), and an optical fiber for coupling light thereinto. RF is coupled into the crystal by a dielectric waveguide which is matched to the crystal. The nonlinear crystal causes the light and RF to interact, to cause products which can be detected at the dielectric waveguide. When used as a modulator or demodulator, the modulated light may be coupled out by a second optical fiber, and or the modulated RF may be coupled out by a second dielectric waveguide. The dielectric waveguide may be transitioned to conventional hollow conductive waveguide.

Abstract: A radar system transmits dispersed pulses, and receives echoes from targets. The echo signals are digitized and applied over a number of signal paths. In each signal path except one, the digitized signal is multiplied by one of a plurality of differential exponential signals, for converting the echo signal of different exponential signals, for converting the echo signal in each path to baseband, with the baseband frequency representing a particular Doppler which depends upon the exponential signal. In the one remaining signal path, no multiplier is used, and the echo signal is deemed to be at baseband. The signals in each path are applied through a cascade of a pulse compressor and a range sidelobe suppressor. Since Doppler filtering has not yet taken place, full compression and range sidelobe reduction is not achieved, because of extraneous pulse-to-pulse phase shifts.

Abstract: A lift vehicle has an elongated support structure affixed to its upper end, with the axis of elongation of the support structure parallel to or coincident with the longitudinal axis of the lift vehicle. The support structure defines a plurality of attachment planes, each of which includes the axis of elongation, which together divide the region about the axis of elongation into N angular sections or regions, each with an included angle of 360.degree./N. A plurality MN of spacecraft are organized into a plurality of M sets or layers, each containing N spacecraft. Each spacecraft defines first and second lateral support planes, skewed relative to each other, which intersect at a line of intersection, is parallel to the axis of elongation when the spacecraft are mounted to the support structure. Two or more spacecraft are mounted in end-to-end position in each angular portion. Each spacecraft stiffens the support structure, so that the stiffened support structure, can sustain the launch forces.