Abstract: A fiber optic terminus (11) comprising a body (13) having a passage (43) therein and a longitudinally compressible and radially expandable coupling element (15) in the passage. The coupling element (15) has a passage (60) therein adapted to receive a portion of an optical fiber (23). An axial force is applied to the coupling element (15) by a plunger (17) and a spring (19). The coupling element (15) is compressed axially and expanded radially to retain the optical fiber (23) in the passage (60) of the coupling element.

Abstract: The transverse member (29) of a reflow soldering heater bar (23) is slotted at intervals to reduce thermal expansion. The slots (63), which typically extend orthogonally through the transverse member (29) and the connecting legs (61) of the heater bar (23), may extend diagonally therethrough to prevent missed welds.

Abstract: A force limiting weld head (11) which includes a supporting structure (13), a pressure barrel (15) and an output member (17) mounted for movement on the supporting structure, a fixed electrode (19) mounted on the supporting structure, a movable electrode (21) driven by the output member, a coupling (23) for drivingly coupling the pressure barrel and the output member. The coupling includes a variable-volume chamber (89) and a piston (77) responsive to overtravel for varying the volume of the chamber.

Abstract: According to the invention, a high-speed digital data communication system employs current mode circuitry as input and output devices at the ends of a transmission line, such as the interconnections between integrated circuit chips. Specifically, a current mode driver switch generates output current amplitudes responsive to a source of a digital signal representative of data to be transmitted. The switch output is connected to the input of a transmission line. The output of the transmission line is connected to the input of a receiving circuit that responds to the current amplitudes and has an input at an approximately constant voltage level. The receiving circuit is a transistor connected in a common base configuration. The emitter of the transistor is connected to the output of the transmission line. The base of the transistor is connected to a constant voltage source. A pulse shaper in the form of a Schmitt trigger has positive feedback from output to input.

Abstract: A method for evaluating characteristics of a printed wiring board by measuring the alternating current impedance spectra of the printed wiring board conductor pattern. The method is useful in evaluating a number of different characteristics, such as moisture content, delamination, interlayer thickness and surface characteristics.

Abstract: Disclosed is a device for making multi-layer crystals. It includes a holder and a plurality of masking elements adapted to be secured successively to the holder. The masking elements have cover pieces that overlie the area protected by the preceding cover pieces and have an additional cover piece. This produces a device having progressively truncated corner sections. There is thus formed a multi-layered crystal having portions adapted to be connected to electrical leads.

Abstract: A normalized frequency domain Least Means Square filter. The feedback coefficient for each frequency bin is adjusted separately in the filter by use of an input power estimate. The power estimate is incorporated directly into the filter algorithm as a data-dependent, time-varying stochastic feedback coefficient. The filter is particularly useful in applications in which the input signal has large spectral variations, which could lead to filter instabilities in some frequency bins if a single feedback coefficient were employed in all frequency bins.

Abstract: An expandable and contractable sealed environment is provided by a rigid frame member and a pair of deformable heat transfer elements fixed to the frame member. The frame member is located between two heat-producing electronic assemblies. A coolant agent is pumped into the sealed environment to flex the membranes and cause them to conformally contact the pair of electronic assemblies. Excess heat in the assemblies is then allowed to pass across the membranes and into the coolant agent for dissipation purposes. In order to remove the electronic assemblies, the pressure of the coolant agent is reduced, which permits the heat transfer element to return to its nondeformed state removed from the assembly. Thus, the electronic assemblies can be removed without the need to open fluid couplings.

Abstract: A method of forming a polymer dispersed liquid crystal (PDLC) film is disclosed which consists of forming a solution of LC dissolved in a monomer, photopolymerizing the solution to form a film having a dispersion of LC bubbles therein, establishing a correlation between the LC bubble size and selected characteristics of the film, selecting a LC bubble size corresponding to desired film characteristics, and controlling the conditions of photopolymerization to achieve said LC bubble size. The LC bubble size is controlled by means of the UV exposure intensity, exposure temperature, exposure wavelength, LC concentration and/or concentration of polymerization initiator. Correlations are noted between LC bubble size and the resulting film's threshold and operating voltages for optical transmission, contrast ratio, absolute transmissivity and electro-optical response times.

Abstract: A rotating reflector is used to provide a beam scan throughout a predetermined angle such as 360.degree.. A circular polarizer is coupled with the reflector and converts received linearly polarized energy into circularly polarized energy. A fixed feed is configured to receive the reflected circularly polarized energy and converts such energy to linearly polarized energy. The antenna system can receive the same linear polarization of energy throughout its 360.degree. scan angle without polarization mismatch or orthogonal polarization losses. The relative orientation of the two polarizers may be adjusted to receive any orientation of linear polarization of energy throughout the scan angle. For example, they may be oriented so that the antenna system receives vertically polarized energy, slant 45.degree. linearly polarized energy, or horizontally polarized energy.

Abstract: A method for application of an adherent nickel plate to titanium includes steps of surface preparation, deposition of nickel from a plating solution, and a final treatment. The surface preparation steps include a hydrochloric acid dip, a nitric acid/hydrofluoric acid activation, treatment to slow the re-formation of an oxide layer, and deposition of a nickel strike. The treatment to reduce oxide formation may be accomplished without application of a current, in a solution of acetic and hydrofluoric acid, in which titanium alloy has been electrolytically dissolved. Alternatively, the treatment may be performed with the piece to be plated made anodic in a solution of acetic acid and hydrofluoric acid.

Abstract: A crystal modulator (20) is on an axis (19) which is positioned in translation and pivotal rotation with respect to another axis (17) of a laser. The crystal modulator (20) is supported in an inner housing (18) on axis (19). The inner housing is supported within an outer housing (16) which is affixed to the laser. Mating surfaces (32, 38) on the inner and outer housings are spherically contoured so that the inner housing may be pivoted about the center (24) of the extended sphere of the mating surfaces and thereby pivot axis (19) into coincidence with axis (17). An end (22) of the crystal modulator is positioned at this spherical center. Of two sets of four setscrews (26, 28) threaded into the outer housing, one set is disposed to contact the inner housing directly. The other set of screws is disposed to contact a ring (36) whose inner surface comprises one of the spherical surfaces.

Abstract: A phase lock loop frequency synthesizer for providing a synthesized frequency signal employing a modified adaptive loop construction having parallel feedback paths about a loop amplifier. A normal feedback path having a narrow bandwidth characteristic includes a feedback capacitor having one end connected to electrical ground via a controlled switch and a second feedback path having a wide bandwidth characteristic with a capacitor also connected across the amplifier. Upon the variation of an incoming reference signal, the controlled switch connects the normal feedback capacitor to ground permitting the wide bandwidth feedback path to rapidly settle the loop while charging the feedback capacitor of the normal feedback path. Upon opening the controlled switch, the narrow bandwidth feedback path completes the charging of the feedback capacitor of the normal feedback loop settling the loop to the steady state condition while enhancing the settling time.

Abstract: A method of fabricating a polarizing dish antenna reflector (10) wherein a light source (22) is employed to pyrolyze an organometallic compound (14) disposed on the antenna surface to form grid elements (24) directly thereon. The surface of the parabolic dish antenna reflector (10) is coated with an organometallic compound (14) that comprises a metallic component such as gold, silver, copper chrome, or other suitable metal. The coated surface may be conditioned by depositing a surface film of polyimide, or the like. The coated surface is then pyrolyzed by using a high intensity focussed light source (22), such as a laser or discharge lamp to form metal grid lines (24) on the surface. The light source (22) is scanned across the surface to create parallel scan lines, or the light source may be fixed and the reflector surface can be moved relative to the light source (22) using a computer controlled XY table (16), or the like.

Abstract: A low profile, mechanical scan antenna having an aperture assembly and a travel guide assembly is disclosed. The aperture assembly is mounted on a carriage for movement along the travel guide assembly which is rotatably mounted for rotation about an azimuth axis. The travel guide assembly includes an arcuately shaped track and the aperture assembly and carriage move along the inside of the arcuately shaped track through the scanning angle. The arcuately shaped track defines an effective antenna gimbal axis which is in front of the antenna aperture.

Abstract: An optical beam scanner incorporating an array of beam deflection elements commonly controlled to steer an optical beam impingent on the array is described. The beam steering elements are arranged in the array as individually controlled elements and the deflection of the beam is accomplished by setting the phase tilt and the phase offset of each element according to a calculation which removes modulo 2.pi. phase shift from the required position relative to a flat plane. Thus, the array elements can be thin and need only supply about 2 radians of phase shift. These elements may be incorporated in a planar array using beam deflection elements such as liquid crystal beam deflectors by choosing a drive scheme representing either a blazed array or a flat piston array.

Abstract: A transparent eyelevel stoplight for vehicles is disclosed, which operates on an upconversion principle wherein red light in an otherwise transparent crystal is excited by invisible infrared radiation. The crystal may take the form of a transparent plate or an optical fiber applied to the vehicle rear window. The host crystal material is doped with a suitable rare-earth ion, which when illuminated by infrared energy produces visible light. An infrared laser may be used to illuminate the doped crystal, and is activated by the vehicle brakes. The crystal material is transparent to ordinary visible light and therefore will not obscure the driver's vision.

Abstract: A cell bypass circuit is disclosed which includes a diode 32 connected electrically in parallel with a cell 20 of a battery 12. A thermal switch 34 is mounted in thermal contact with a diode 32. A relay 38 including a coil 36 and a contact 40 is provided. The coil 36 is connected to the thermal switch 34 so as to be activated by the activation thereof. The contact 40 of the relay 38 is connected in parallel with the cell 20 so that the activation of the diode 32 causes thermal energy to radiate therefrom activating the thermal switch 34. The activation of the thermal switch 34 causes the activation of the relay 38 which in turn places an electrical short across the defective cell 20 via the contacts 40 thereof.

Abstract: Beams of energetic atoms are produced by furnishing a beam of energetic ionized clusters and disintegrating the clusters to produce a beam of energetic atoms. The energetic ionized clusters are provided by forming a beam containing uncharged particles, both clusters and atoms, ionized the particles, accelerating the particles, separating any unionized particles from the beam, and removing those particles outside a selected size range from the beam. The resulting energetic beam of ionized clusters is impacted against a cluster scattering plate so that the clusters break apart into unclustered atoms and ions. The ions are removed from the beam of unclustered atoms, which is available for use as needed. The atoms have energies dependent upon the cluster beam conditioning, but which are typically in the range of 1-10 electron volts per atom.

Abstract: A low noise system and method for both amplifying and retroreflecting an information-bearing probe beam employs a two-wave mixer in conjunction with a pseudoconjugating element. The probe beam is amplified by two-wave mixing in a photorefractive medium, while the pseudoconjugator is arranged to retroreflect the amplified probe beam back through the photorefractive medium such that optical distortions imposed upon the beam during the amplifying pass are compensated, yielding an output with a high signal-to-noise ratio. Various types of pseudoconjugating elements may be used.