Abstract: A high speed logic circuit having extremely low propagation delays, suitable for implementation in III-V technology. A logic stage provides the desired logic function by combining a predetermined number of input FETs. The drains of the input FETs couple to a pull-up FET and form a first intermediate output of the logic stage. The sources of the input FETs couple to a pull-down FET and form a second intermediate output of the first stage. A second stage, or buffer stage, responding to the intermediate outputs of the first stage, provides sufficient drive to an output terminal of the logic gate to drive multiple loads (gates) coupled thereto. The second stage includes a pull-down FET responsive to the second intermediate output of the first stage. The second stage also includes alternative combinations of FETs and diodes to pull-up the voltage on the output terminal of the logic gate.

Abstract: Method and apparatus are disclosed for establishing a wideband communication facility from a plurality of narrow bandwidth channels through a switched communications network from a first to a second terminal in response to a call from the first terminal indicating a customer-selected bandwidth for the wideband facility. Apparatus is also disclosed for establishing a wideband communication path through an illustrative switching system interconnecting groups of narrowband time division multiplexed channels established for the wideband facility. The path has a bandwidth greater than any of the TDM channels. Additional buffer memories and memory control arrangements are added to the initial and final stages of a time-space-time switching network to prevent any of the time slot data of a given time frame from being delayed and included in another time frame.

Abstract: A feed forward circuit receives an input signal having at least one carrier therein in a prescribed frequency range. The input signal is applied to a first circuit path having a power amplifier that produces an output signal with a distortion component and to a second circuit path that delays the input signal without distortion. The output signal of the first circuit path is combined with the output signal of the second circuit path to form a signal representative of the distortion component of the first circuit path output signal and the distortion component representative signal is subtracted from the output signal of the first circuit path to cancel the distortion component therein. The prescribed frequency range of the first circuit path output is scanned to detect a carrier signal and the amplitude and phase of the signal in the first circuit path is modified to minimize the magnitude of the detected carrier in the distortion representative signal.

Abstract: A coupling (20) for backplane connections of an optical fiber arrangement facilitates superbly alignment of optical fibers notwithstanding blind insertion of a portion of the arrangement. The coupling arrangement includes a housing (70) which has a first end portion (52) and a second end portion (49) and which is mounted in an opening of a panel (32) such that it floats and is capable of three dimensional adjustive movement to facilitate alignment of plugs which terminate optical fibers and which are inserted into opposite ends of a sleeve (84) disposed in the housing. A longitudinal movement of the coupling is facilitated by a compression spring (102) which is disposed about the housing between the backplane and a retaining member (104).

Abstract: An optical fiber communications system with Raman amplification of the signal radiation comprises a broadband pump radiation source, or, preferably, a multiplicity of pump radiation sources and polarization maintaining optical fiber as the transmission medium. The sources are selected to result in a pump radiation spectrum having individual spectral components such that pump radiation intensity for each spectral component in the desired polarization in the fiber core is less than a critical intensity I.sub.c. In particular, the average intensity of pump radiation in a first spectral interval, centered on any wavelength .lambda..sub.p in the pump radiation spectrum and of width equal to the Brillouin line width of the fiber at .lambda..sub.p, is to be less than that average intensity in the first spectral interval that results in conversion of 10% of the radiation in the first spectral interval to stimulated Brillouin radiation.

Abstract: In an optical fiber connector in which each of two optical fibers (21-21) is terminated by a plug (40) having a passageway (41) for receiving an end portion of the optical fiber, eccentricity of one fiber end relative to the other is reduced by causing each optical fiber to be mounted in a specified orientation with respect to its associated plug passageway.

Abstract: Novel superconductive Pb-substituted oxides are disclosed. The oxides all have layered perovskite-like crystal structure, and manifest superconductivity (R=o) above about 77K. The materials are described by the nominal formula X.sub.2+x M.sub.3-x Cu.sub.2 O.sub.8.+-..delta., where X is Bi and Pb, M is Sr and Ca, 0.ltoreq..times..ltoreq.0.3, 0.ltoreq..delta..ltoreq.0.5, the Pb/Bi ratio is between about 0.2 and about 0.5, and the Sr/Ca ratio is between 0.5 and 2.

Abstract: Disclosed in a compact and inexpensive coaxial connector and jack assembly. The spring member which makes the ground connection to the coaxial cable is designed with sufficient rigidity so that the standard sleeve member surrounding the spring is eliminated.

Abstract: A QDPSK communication receiver includes a frequency source, apparatus for translating a received QDPSK signal having inphase I and quadrature phase Q components to baseband and a baseband demodulator. For each symbol period of the baseband QDPSK signal, a signal (I.sub.diff) representative of the inphase component of the phase different between immediately successive received symbols and signal (Q.sub.diff) representative of quadrature phase component of the phase difference between immediately successive received symbols is formed. In order to synchronize the frequency of the receiver frequency source to carried frequency of the received QDPSK signal, a preamble interval is defined during which a sequence of identified symbols is received.

Abstract: A solder joint assembly technique applies controlled volumes of solder to pads of both package and substrate. The two units are positioned adjacent each other with the pads and solder deposits mechanically maintained in registration with each other. The assembly is reflowed and the final separation between package and substrate at which the resulting solder joint solidifies is mechanically controlled in order to control a geometry of the resultant solidified joint. The solder volume deposits may assume various forms including spherical bumps and solder paste deposits.

Abstract: Certain semiconductor device structures are described in which single crystal layers of cubic Group II fluorides cover at least part of the surface of III-V semiconductor compound. The fluoride crystal has a cubic structure and may be lattice matched or lattice mismatched to the compound semiconductor substrate depending on fluoride composition. These fluoride single crystal layers are put down by a moleuclar beam epitaxy procedure using certain critical substrate temperature ranges and a particular cleaning procedure.

Abstract: A forced encapsulation system and method that can be advantageously used to encapsulate cable splices e.g., multiconductor communications cables. Containment means are formed around a substrate comprising part of at least one cable, and secured to the cable, thereby forming an enclosure into which liquid encapsulant can be introduced under pressure and in which the encapsulant can be maintained at pressure above ambient pressure. In a preferred embodiment, the containment means comprise a containment bag formed in situ from an elastomer sheet and sealed to the cable sheaths, with a reinforcing outer enclosure surrounding the containment bag.

Abstract: A mineral-oil-free composition of matter useful as a cable splice encapsulant comprises between about 20% and about 60% polyurethane, by weight of the cured encapsulant, the balance comprising plasticizer(s) and optionally, additives such as catalysts, antioxidants and fungicides.

Abstract: A redundant (multiple) bus system for interconnecting a plurality of data source and destination entities and arranged to direct data communications over an alternative bus in the event that a prior call to a destination over a first bus was unsuccessful. Each source entity maintains a table designating a separate logical path over each bus to each destination entity, marking each path designation in accordance with the success or failure of calls directed through the path. The bus selection for delivering a communication to any destination is determined in accordance with designation markings for the paths to the destination and independent of designation markings for paths to other destinations whereby a bus may be selected for a delivery to one destination even though prior deliveries over the bus to other destinations have failed.

Abstract: The operation of neural networks begins with the initialization of the system with the information to be processed. Presently, this initialization is performed by pinning the system with rather large analog or digital signals representing this information. The problems associated with the high power required for such initialization are eliminated and accuracy is maintained by utilizing a specific set of input points and appropriately positioned switches. In particular, a switch corresponding to each amplifier is introduced, and the initializing data is introduced between the amplifier and this switch.

Abstract: An animal-resistant optical fiber cable (20) includes a core (22) which comprises a transmission medium and a sheath system. The sheath system includes an outer jacket (65) and a dielectric armor (40) in the form of a shell. The shell comprises a plurality of longitudinally extending preformed segments (42--42) each having an arcuately shaped cross section transverse to a longitudinal axis of the cable and each comprising glass fibers embedded in a matrix material. Each of the segments covers less than half of the periphery of the core and, in a preferred embodiment, eight segments are used. Further, the shell segments are stranded helically about the core with longitudinal edge surfaces of adjacent segments being in engagement with each other. The shell segments not only provide rodent protection for the cable, but also they provide suitable tensile and compressive strength. Further, because the cable has an all-dielectric sheath system, it is inherently lightning, corrosion and EMP resistant.

Abstract: Apparatus comprising a bakeable high vacuum system using cryopumps is disclosed. Auxiliary cooling means in thermal contact with the primary pumping stage of the cryopump remove heat from the cryopump, whereby the walls of the cryopump may be heated during operation of the cryopump, such that the cryopump can be baked. This can result in substantially improved attainable pressure in the system.

Abstract: A method for forming articles which include silica-containing glass bodies, as well as the resulting articles, are disclosed. In accordance with the method, silica-containing gel particles are fused to form a glass body. In contrast to previous such methods, these particles are formed by mechanically, substantially uniformly subdividing either a substantially cohesive gel body, or an ungelled or partially gelled sol capable of yielding a substantially cohesive gel body, to form substantially uniformly sized, wet gel particles. Significantly, only substantially cohesive gel bodies which are also substantially elastic are useful in the invention, i.e., mechanical subdivision of non-elastic gel bodies results in these bodies undergoing plastic flow to yield non-particulate, pasty masses.

Abstract: A call coverage arrangement in which coverage personnel are informed of the switch-hook status of covered terminals by way of a single two-part indicator on the coverage terminal. The two-part indicator indicates switch-hook status for any one of a number of covered terminals. The first part of the indicator identifies the covered terminal and the second part defines the switch-hook status of the identified terminal. The arrangement is flexible in providing coverage for additional terminals and in providing coverage via forwarding from any termianl, since there is no need to assign and dedicate status indicators to particular terminals.

Abstract: An automatic gain control circuit for an amplifier operating over a prescribed frequency range detects the output level of the amplifier; and couples a repeated predetermined waveform occurring at a rate greater than the reciprocal of twice the upper frequency of the prescribed frequency range to the output level signal. The waveform varying level signal is compared to a reference threshold to control the gain of the amplifier through a switched resistive elemement in the amplifier feedback path. The repeated waveform variations about the amplifier output level causes the value of the switched resistance to vary as a function of the output level. A low pass filter connected to the amplifier output removes switching transients resulting from the high frequency changes in the switched resistive element. The gains of a plurality of amplifiers may be determined by a common control for accurate tracking over a wide dynamic range.