Abstract: A method for determining crystallographic orientation of an InP substrate wafer includes the steps of immersing at least a portion of the substrate wafer in a chemical etchant for a predetermined amount of time to expose features having a predetermined shape and designating a particular crystallographic direction on the substrate wafer in accordance with relative positions of features on the portion of the substrate wafer.

Abstract: A low-loss single mode fiber with low total dispersion within the wavelength range 1.25-1.385 .mu.m and low added cabling loss is disclosed. The fiber has relatively high .DELTA. to assure low cabling loss. The high .DELTA. is obtained, however, without paying a cost in high material dispersion by providing at least 20 percent of the .DELTA. by down-doping of the fiber cladding.

Abstract: A graphic display terminal is arranged to receive from a sending source drawing instructions containing the description of a display character. The terminal, under control independent from the sending source, interprets each received drawing instruction into a particular picture description bit pattern tailored to the characteristics of the terminal display device. The interpreted bits are then stored in a graphic repertory for subsequent retrievel under control of code received from the sending source. In this manner dynamically redefinable character sets may be created and used without regard to a particular terminal implementation.

Abstract: The present invention relates to a feed arrangement for use with compact scanning beam antennas which comprises a linear phased array of small feed elements (10) which form an approximate line source that radiates a wedge-shaped cylindrical beam toward a subreflector (12) which is shaped to focus the wedge-shaped cylindrical beam to a point source which then produces a spherical wavefront. The spherical wavefront can then be focused by a main reflector (14) into linear scanning beams if desired. Multiple linear phased arrays of small feed elements can be disposed parallel to each other to form a multibeam feed arrangement for producing multiple fixed or scanning spot beams.

Abstract: A mechanized system distributing the access, test and communication functions to the point of testing, typically the centralized switching facility serving the telephone loops and equipment to be tested. Computer (200) stores information about each subscriber loop in the geographical area served by a system. Front-end computers (220,221) interact with computer (200) to retrieve pertinent data regarding loops to be tested. Each switching facility in an area includes a loop testing system (e.g., 160) that implements the required functions. The communication functions residing in front-end computers (220,221) and loop testing systems (160,161) are coupled via a data communication network (140) in a manner that allows any front-end computer to communicate with any loop testing system. Users of the system control access and test from consoles having the capability of establishing independent communication paths over the national dial network for interactive tests on loops accessed through standard test trunks.

Abstract: Various implementations of a technique are presented for capitalizing on signal correlation in a manner for providing usable frequency information. In a specific embodiment, a filter (51) is adapted to a signal component of an input signal using a variable generated by an adapter (58). The variable has a prescribed relationship to the frequency of the signal component. The variable is used to weight a combination of signal values derived from past signal history to form a prediction of a future signal. An adder (56) combines the new signal value with the prediction to form an error signal which is used by the filter (51) and the adapter (58). When the filter converges, a frequency indicator (59) using the variable provides an output signal indicative of the frequency of the signal component.

Abstract: Aluminum electrically conducting patterns for integrated circuits are achieved with narrow lines and unexpectedly-high electromigration characteristics by making the crystal grains of the pattern into a chain-shaped structure with {111} orientation. A process for achieving the structure is also described.

Abstract: A double barrier double heterostructure laser is described in which relatively narrow beam divergence is obtained by the presence of wide bandgap, with respect to the cladding layers and barrier layers intermediate the active and cladding layers.

Abstract: An electro-optic integrated circuit is disclosed wherein the long electrical connections normally present on a large scale integrated circuit are replaced by an optical waveguide layer. A plurality of epitaxial layers are grown on a single substrate and at least three of the plurality of epitaxial layers are grown with bandgaps that are suitable for optical sources, detectors and waveguiding. These primary layers are separated from each other by a barrier layer having a bandgap greater than either of the adjacent primary layers. Two of the layers adjacent to the substrate are grown to accommodate electrical devices that can be used to couple electrical signals to the optical source layers and to amplify electrical signals provided by the optical detection layer.

Abstract: Regioregular polyfluoroethylenes are produced by a specific set of reaction steps. A precursor polymer for the regioregular polyfluoroethylene is produced by using the monomer typically employed for producing the particular polyfluoroethylene and introducing a blocking group such as a chlorine atom. Polymerization of such fluoroethylenes with blocking groups to polyfluoroethylenes produces a corresponding regioregular precursor polymer. The blocking group is then replaced by a hydrogen with a reagent such as an alkyltin hydride. The resulting polymer is the desired polyfluoroethylene which has a regioregularity.

Abstract: A process is described for the electrodepositon of copper on various surfaces. The process involves use of a nonconsumable counterelectrode. Of particular significance is the composition of the surface of the counterelectrode. The surface of the counterelectrode comprises iridium oxide and tantalum oxide. Such processes can be carried out at high speeds, with smaller and more efficient equipment and can use various copper compounds as a source of copper.

Abstract: An arrangement in a telephone system providing for the handling of calls which have been automatically redirected to a call covering station in a customer premises telephone system. The covering station is equipped with one or more function buttons each for activating a different call processing function on a covered call at the covering station. The arrangement automatically identifies the intended principal station on a covered call and performs the necessary operations associated with an operation of one of the function buttons with respect to the principal station in question regardless of how many principal stations are covered by the covering station, thereby eliminating direct station selection (DSS) keyfields or the dialing of principal station numbers from the covering station.

Abstract: A process for forming chanstops in complementary transistor integrated circuit devices which involves only a single extra masking step yet permits close control of the doping in the chanstops. The process is advantageously used starting with a twin-tub structure for forming CMOS integrated circuit devices.

Abstract: A call coverage arrangement in a telephone system. Any station served by the system may be assigned to a call coverage group as a principal station. A coverage group includes the identities of a plurality of call covering stations for the principal station and an indication of the order of preference of the covering stations. Call coverage criteria are stored for principal stations specifying circumstances under which calls intended for the principal stations are redirected to coverage. A covered call is redirected sequentially to each of the covering stations in a coverage group in the order of preference until the call is answered or abandoned. The coverage criteria include options based on both the state of a principal's station (active, busy, idle, etc.) and the class of an incoming call (internal, external, priority). Principal stations are equipped with a "send all calls" button.

Abstract: Disclosed is an eight-mask twin-tub CMOS process which forms contiguous p- and n-tubs in a relatively lightly doped bulk region in a self-aligned manner using a single masking step. The process also forms the sources and drains of the p- and n-channel transistors with a single masking step by first nonselectively implanting p-type impurities into all source and drain regions and then selectively implanting n-type impurities into only the source and drain regions of the n-channel transistors in amounts sufficient to overcompensate the p-type impurities therein.

Abstract: A transmission link is established between remote electrical transducers, e.g., underwater, and a monitoring receiver, e.g., shore-based, over an optical fiber link using integrated optical waveguides. Optical directional couplers with absorber and reflector elements incorporated in the waveguides at respective terminals of the transmission link permit the injection of light into the fiber at the monitoring terminal and the modulation of reflected light at the transducer terminal in accordance with an electrical signal from the transducer. No electrical energy then needs to be transmitted between the monitoring and transducing terminals of the transmission link. The link itself is thus light in weight and free of electrical currents subject to electromagnetic interference.

Abstract: An ADPCM coder (100) converts a linear PCM input signal representative of PCM encoded speech or voiceband data into a quantized n-bit differential PCM output signal. Samples of the PCM input signal are delivered to a difference circuit (11) along with a signal estimate of the same derived from an adaptive predictor (12). The resultant difference signal is coupled to the input of a dynamic locking quantizer (DLQ). A quantized version of the difference signal is delivered from the output of said quantizer to an algebraic adder (17) where it is algebraically added with the signal estimate. The result of this addition is coupled to the input of the adaptive predictor, which in response thereto serves to generate the next signal estimate for comparison with next PCM sample. The adaptive quantizer has two speeds of adaptation, namely, a fast speed of adaptation when the input linear PCM signal represents speech and a very slow (almost constant) speed of adaptation for PCM encoded voiceband data or tone signals.

Abstract: An AC-AC line current reversal technique is employed for generating a telephone ringing signal. Generation of the signal is accomplished by controllably activating one of two series full wave rectification circuits responsive to a transformer coupled AC signal during alternate periods at a rate substantially equal to a desired ringing signal frequency.

Abstract: ABS thermoplastic material is rendered electrically conducting by the inclusion of carbon particles. When manufactured by a process of dry mixing of ingredients, melting, and molding, the material has desirably low sheet resistance even at relatively low levels of carbon content (as is desirable in the interest of plastic formability). The new material may be used in the manufacture of electret microphones.

Abstract: A region of saturable absorption is produced in semiconductor lasers by proton bombardment and results in subpicosecond optical pulses.