Abstract: This invention involves optical fiber which supports essentially only a single guided mode, perhaps degenerate, at the transmission wavelength, usually between 0.6 and 1.7 microns. The index of refraction of the core material is graded in the radial direction so as to yield an optical fiber with very low total dispersion and therefore high bandwidth. Specific embodiments include, in addition to the low dispersion characteristic, improved field confinement, and therefore permit lower clad-to-core ratios then heretofore believed practical. Additional advantages which accrue as a result of the greater field confinement include lower cabling, microbending, and curvature-induced losses.

Abstract: A mounting arrangement for an integrated circuit leadless chip carrier (13) for providing compliance to prevent solder joint failures due to stress and differential thermal expansion. A supporting substrate board (10, 20, 30) has bonded to one surface a flexible sheet (11) carrying printed wiring (12) to which the carrier (13) is electrically connected by means of solder pedestals (19). At each of the latter connections the board (10, 20, 30) presents recesses (15, 22, 31a, 33a) over which the sheet (11) is freely suspended to provide free sheet portions (18) which absorb the stress and differential expansion to protect the solder connections.

Abstract: The present invention relates to phased array antenna arrangements which comprise a linear array of feed elements where the array has an aperture which is out at a bias angle along the minor axis of the array to produce a fixed linear phase taper along the minor axis by all elements. Then by linearly scanning the array along the major axis of the aperture of the array, a beam is scanned along an arc which can be made to correspond to an orbital arc segment around a celestial body and within the field of view of the antenna arrangement when the bias angle is properly chosen. The feed elements can comprise long feedhorns or horn antenna configurations which can be used in a separate array or disposed in an array on a conjugate plane of a main cylindrical reflector when used in multiple reflector phased array antenna arrangements.

Abstract: A magnetic bubble detector for an ion-implanted bubble memory is achieved by using a permalloy detector element and two conductors. The conductors are operative first to stretch a bubble from one position in a bubble path and then to destretch it, after detection, from the detector element to another position in the path. The detector has been operated at 100 kilohertz.

Abstract: An electrically heated soldering device adapted to simultaneously heat a plurality of spaced electrical elements in a reflow soldering operation includes an elongated metal laminate of substantially U-shaped cross section having a bight portion between two side portions which may be parallel or divergent. The laminate includes a layer of aluminum between a layer of copper and a layer of stainless steel, with the layers being roll bonded together. The copper and aluminum layers are removed at the bight portion to expose the stainless steel layer and form a heat generating zone for contacting the plurality spaced electrical elements which is corrosion resistant and nonwettable by solder. The edges of the copper and aluminum layers adjacent to the exposed stainless steel bight portion are shaped to impart a selectable temperature profile, either uniform or non-uniform along the length of the bight portion.

Abstract: A time division multiplex (TDM) switching network is disclosed in which at least part of the network comprises a space switching portion (TMS) and in which the need for duplication of the space switching portion, and like methods of achieving network reliability, is eliminated. Data from an incoming channel is partitioned into successive blocks, a prescribed number of which form a set of blocks. The blocks are of predetermined size. Each of the blocks of a set is switched via different paths of the space portion of the network. A single network fault can therefore cause the loss of only one block of data in a set. This loss can be made insignificant in the case of data representing telephone conversations. For data not representing telephone conversations, error checking and correcting information is added to the set before transmission through the space portion of the network and errors occurring during transmission are corrected thereafter.

Abstract: A method of contouring crystal plates for frequency control. After plate dimensions are established, the plates are kept in a stack separated by a bonding material. The stack is immersed in an etchant which etches the exposed crystal edges in a manner which undercuts the bonding material, thus batch forming bevel contours on at least the outer portions of the major faces of each plate in the stack.

Abstract: Weighted sums of samples of an interference-corrupted data signal are generated to form phase-compensated, symbol-spaced samples. The interference-corrupted signal is at the same time subjected to conventional adaptive equalization and is otherwise processed so as to form tentative decisions as to the transmitted data. Cancellation signals representing the interference components of the phase-compensated samples are generated by forming respective weighted sums of the tentative decisions and each cancellation signal is combined with a respective phase-compensated sample to provide cancelled samples from which final data decisions are made. The weighting coefficients used to form the phase-compensated samples and the cancellation signals are adaptively updated in response to error signals derived from the difference between each cancelled sample and the corresponding final decision.

Abstract: To substantially increase the bandwidth of a random access memory (RAM), a shift register is disposed within the memory array such that the shift register lies parallel to the word lines and is connected to at least individual ones of the bit lines contained within the array. Separate high-speed serial input and output lines are provided by the shift register. These lines are in addition to and operate independently of the slower speed input and output lines normally provided by the RAM. Through this arrangement, a row of data can be transferred to and from the memory array at a rate substantially faster than the single-bit access rate of the RAM.

Abstract: The fade character of a transmitted radio signal comprising an amplitude or phase modulated double-sideband signal is determined from the algebraic sign of the fade induced modulation and the location of the fade notch (.omega..sub.f) relative to the center (.omega..sub.c) of the double-sideband signal frequency spectrum. In the disclosed embodiment, the algebraic sign of the fade induced modulation is determined (e.g., 402, 403, 404, 405, 406, 409, 410, 411, 412, 413, 417) from the sign of the dc component of the product of the differentiated amplitude modulation and frequency modulation of the received signal. The relative location of the fade notch is determined by comparing the amplitudes (e.g., 402, 404, 405, 406, 415) of corresponding frequency components in each sideband of the received double-sideband signal.

Abstract: A display cell having at least two states of different opacity, comprises a first material having a first index of refraction, a second material dispersed within the first material and having a second index of refraction, the difference between the first and the second indices of refraction being variable over a range of values, and means for varying the difference in index of refraction over a portion of the range. When the indices of refraction of the first and second material are substantially the same, the display is substantially transparent. Otherwise it is opaque or substantially less transparent.

Abstract: The subject precision isolation amplifier adds error correction circuitry to a basic isolation amplifier circuit to thereby produce an error-free output signal comprising only the metallic component of the monitored voltages. The error correction circuit consists of a pair of up/down emitter followers and a current mirror circuit which function to eliminate both the longitudinal components of the monitored voltage signals and the voltage offset generated by the basic isolation amplifier. A second error-free ouput signal comprising only the longitudinal component of the monitored voltage signals is also provided.

Abstract: A segmented plasma excitation and recombination (SPER) device is employed in a deposition scheme in which the plasma generated in the gap between adjacent electrodes is formed into a beam of ions/atoms by flowing a background gas through the gap. The beam strikes a workpiece and deposits a layer of the vaporized electrode material thereon. Also described are techniques where the ions react with workpiece or the background gas to form a layer, as well as where the ions bombard the workpiece to etch away a layer.

Abstract: Apparatus, and associated methodology, for testing an open in a pair from a shielded, multipair cable contaminated by water to correct the measured distance to the open from a measurement point and thereby obtain the true distance comprises: means (501) for applying an AC source (100) to the mate (101) of the open conductor (102); means (503,504) for detecting the resultant voltage induced on the open conductor through the capacitive coupling effects of the pair; and means (510) for determining the percentage length of the pair affected by water from the source and resultant voltages and for estimating the true distance by correcting the measured distance as a function of this percentage.

Abstract: Apparatus for mounting an integrated circuit module (2) on a printed wiring circuit board (3). The apparatus assembly (1) comprises electrical conducting members (10) for interconnecting the module with the circuit board and an insulating base (11) transversely mounting the electrical conducting members to position quadrilateral configurations of first and second spring contacts (102, 105) in planes parallel to top and bottom surfaces of the insulating base. A one piece cover (12, 42) engages the insulating base to spring clamp the module thereon and maintain each module terminal (20) in electrical engagement with a corresponding one of the first and second spring contacts.

Abstract: The present invention relates to an array phasing technique which normally provides directional spotbeams, and in the event of a failure mode of a phase shift controller for providing a wide area coverage beam. In an arrangement for practicing the present technique, each array feed element has disposed at its input a serial arrangement of a fixed value phase shifter (32) and a variable phase shifter (34). Each variable phase shifter has a separate control signal supplied to it by a phase shift controller (36). During normal operation the combined fixed value and variable phase shifters cause the array to radiate a flat wavefront in a predetermined direction, and in a failure mode of the phase shift controller the fixed phase shifters cause the array to radiate a diverging area coverage beam.

Abstract: In a data receiver (100), sampling circuitry (120, 125) forms samples of a received data signal representing a succession of data symbols. The samples, which are formed at twice the symbol rate, are multiplied by respective ones of a queue of coefficients in a fractionally spaced equalizer (150). Further circuitry (155, 160, 165, 170) forms decisions in response to the resulting products as to the values of the tansmitted symbols and generates error signals. The values of the coefficients are updated in the equalizer in response to the error signals. Timing recovery circuitry (230) within the equalizer periodically identifies the largest of the coefficients and either advances or retards the phase of the sampling circuitry depending on whether that coefficient is or is not within a predetermined portion of the queue. The magnitude of the amount by which the phase is advanced or retarded is determined by the position of the largest coefficient relative to the center of the coefficient queue.

Abstract: A method of coating uncoated portions of a coated optical fiber is disclosed. In this method a grooved split mold apparatus is used. This fiber, including coated portions of the fiber are placed within the groove and appropriately tensioned so as to prevent contact between the uncoated portions of the fiber and the mold. Injection molding techniques are then used to recoat the uncoated portions of the fiber.

Abstract: A digital regenerator line includes in each station a status and error detection arrangement having an error detection circuit (64) responsive to a filtered composite output signal (101) from a low-pass filtered output from a digital regenerator (30) using quantized feedback. The filtered composite signal includes a stressing signal and a quantized feedback error burst. A high-pass filter (71) is responsive to the filtered composite signal for removing the stressing signal and for passing the quantized feedback error burst. First and second threshold comparators (72 and 76) responsive to the quantized feedback error burst produce a burst signal when the amplitude of the quantized feedback error burst crosses a predetermined threshold (V.sub.R1 or V.sub.R2). The occurrence of the burst signal is determined to indicate that an error has occurred in the output of the digital regenerator.

Abstract: Single wall domains are moved synchronously in a sheet of magnetic material along channels defined by magnetically soft overlays as an in-plane magnetic field reorients. A detector is described which includes as an integral part thereof a portion of the overlay defining the propagation channels.