Patents Assigned to American Telephone and Telegraph Company
  • Patent number: 4937643
    Abstract: A method for fabricating a device which includes a tantalum silicide structure, and which is essentially free of conductive etch residues, is disclosed. The method includes the steps of depositing tantalum and silicon onto a substrate, patterning the tantalum and silicon, and then sintering the patterned tantalum and silicon to form a patterned layer of tantalum silicide.
    Type: Grant
    Filed: July 27, 1987
    Date of Patent: June 26, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Jean S. Deslauriers, Hyman J. Levinstein
  • Patent number: 4937771
    Abstract: A mounting arrangement for diskette drives in a cabinet of electronic apparatus includes an assembly for accommodating two diskette drives or one diskette drive and a removable diskette storage unit mounted in the space reserved for the second diskette drive. The assembly is adapted for quick and easy mount/dismount in and from the cabinet and the removable storage unit provides a convenient storage space for a number of often used diskettes in a space which is typically wasted until installation of a second diskette drive unit is required.
    Type: Grant
    Filed: November 30, 1988
    Date of Patent: June 26, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Norbert A. Rumps, Jr., Mark T. Sodoma, Kiyoshi Suzuki
  • Patent number: 4937870
    Abstract: A speech recognition arrangement where nonspectral features of the input signal, e.g., energy and voicing parameters, are used to effectively remove non-speech events from consideration but only after a time warping procedure based solely on the input and reference pattern spectral parameters has been completed. The time warping procedure is not unduly complex because there is no need to weight spectral and nonspectral parameters in matching input and reference patterns. For each reference pattern, the time warping procedure defines a scan region of the input signal to be used in evaluating the nonspectral input signal characteristics. Energy and voicing parameters are useful in distinguishing non-speech events since speech patterns typically have few very low-energy frames (other than frames that are part of a gap within a vocabulary item) and more than a minimum number of voiced frames, e.g., frames corresponding to vowel sounds.
    Type: Grant
    Filed: November 14, 1988
    Date of Patent: June 26, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: Robert W. Bossemeyer, Jr.
  • Patent number: 4937653
    Abstract: Integrated circuit chip-to-chip interconnections are made via gold pads on each chip that are bonded to corresponding gold pads on a silicon wafer chip carrier. The pads on the chips and/or the pads on the carrier are characterized by texturing (roughening) with a feature size of the order of a micrometer or less, so that each of the pads on the chip can be attached to each of the pads on the carrier by compression bonding at room temperature--i.e., cold-well bonding. In particular, the texturing of the gold pads on the silicon carrier is obtained by etching V-grooves locally on the surface of the underlying silicon carrier in the regions of the pads, thermally growing a silicon dioxide layer on the silicon carrier, and depositing the gold on the silicon dioxide layer.
    Type: Grant
    Filed: July 21, 1988
    Date of Patent: June 26, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Greg E. Blonder, Theodore A. Fulton
  • Patent number: 4934785
    Abstract: Disclosed is an optical fiber connector that comprises two right capillary cylinders or "plugs", an alignment sleeve that contactingly maintains the plugs in substantially fixed relative relation, and means for maintaining the plugs in substantially fixed relative axial relation. Connectors according to the invention can have very low insertion loss, are easily field-installed, can be easily and relatively inexpensively manufactured, and are useful for single mode as well as for multimode fiber applications. In a preferred embodiment the connector takes the form of the ST.RTM. connector.
    Type: Grant
    Filed: February 23, 1989
    Date of Patent: June 19, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Terry D. Mathis, Calvin M. Miller
  • Patent number: 4934818
    Abstract: A monochromatic light beam scans a silica reference and a translucent body, both submerged in index matching fluid and the deflection angle of the beam is measured as it exits the reference, the translucent body and the fluid. This deflection angle of the light beam exiting the reference is compared with the undeflected beam passing through only the fluid. The difference, if any, is used to offset the measurements of the deflection angles of the light beam exiting the translucent body to correct them so that the profile is referenced to the index of silica.
    Type: Grant
    Filed: March 24, 1989
    Date of Patent: June 19, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Werner J. Glantschnig, Knut D. Pohl
  • Patent number: 4935382
    Abstract: A semiconductor epitaxial device structure is described in which there are alternate single crystal layers of semiconductor, insulator and semiconductor. A typical example is InP/CaF.sub.2 /InP. A process for producing such a structure is also described.
    Type: Grant
    Filed: October 31, 1988
    Date of Patent: June 19, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Wilbur D. Johnston, Jr., Charles W. Tu
  • Patent number: 4933317
    Abstract: A new class of Bi-based superconductive oxides is disclosed. As do the previously known Bi-based superconductors, the novel materials have a perovskite-like crystal structure. However, in contradistinction to the prior art materials, the inventive materials have unmixed B-site occupany, with all substituents occupying A-sites. This tends to produce marginal stability and enhanced transition temperatures, as compared to the prior art Bi-based oxide superconductors. Materials according to the invention have composition ABiO.sub.3-.delta., with A being Ba and at least one monovalent element (typically chosen from Na, K,Rb, and Cs) and 0.ltoreq..delta..ltorsim.0.1, and have a transition temperature T.sub.c.sup.onset .gtorsim.13K. The superconductive materials are advantageously produced from precursor material that contains an excess of the monovalent element(s), as compared to the final composition.
    Type: Grant
    Filed: April 25, 1988
    Date of Patent: June 12, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: David W. Johnson, Jr., Leonard F. Mattheiss
  • Patent number: 4931670
    Abstract: A novel logic gate, using Gallium-Arsenide technology, that is compatible with TTL or CMOS logic. This logic gate operates off a single voltage supply (e.g. 5 volts) and implements complex logic functions within a single logic gate, such as "AND-OR-INVERT". This is accomplished by having at least one FET with the gate terminal coupling to a current limiter, a first source/drain terminal coupling to the input of a logic sub-circuit, such as a DCFL circuit, and a second source/drain terminal coupling to the input of the logic gate. A diode disposed between the first source/drain terminal and the input to the logic sub-circuit sets the switching voltage of the logic gate. Parallel-connected FETs performs the logical "AND" sub-function while the logic sub-circuit performs the logical "OR" and "INVERT" sub-functions. Also disclosed is a buffer circuit for driving large loads while providing large output voltage swings.
    Type: Grant
    Filed: December 14, 1988
    Date of Patent: June 5, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: Tah-Kang J. Ting
  • Patent number: 4929064
    Abstract: Electromagnetic radiation is modulated in response to an electrical signal which produces a variable electric field in a semiconductor .delta.-doped structure. A resulting device has a desirably broad wavelength range in which light intensity can be modulated, large contrast ratio between transparent and opaque states, small operating voltage, and high-speed capability as desirable in optical communications applications.
    Type: Grant
    Filed: July 21, 1988
    Date of Patent: May 29, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: Erdmann F. Schubert
  • Patent number: 4926538
    Abstract: A universal nest (1)) for accommodating a separate one of a pair of ribbon connectors (12 and 12') of heights h.sub.1 and h.sub.2, respectively, comprises an elongated beam (26) along which a first block (28) of a height h.sub.1 is slidably mounted. A slide (42) is slidably mounted on the upper surface (34) of the first block (28) for movement between a first position at which it overhangs a portion of the block to expose part of its upper surface, and a second position at which it overlies the upper surface (34). When the slide (42) is at its first position, the upper surface (34) will support an end of the first connector (12). The slide, when displaced to its second position, itself supports an end of the second connector (12'). A second block (60), having a pair of opposed shelves (66 and 68) of a height h.sub.1 and h.sub.2, respectively, is rotatably mounted to the beam (26) distant from the first block (28).
    Type: Grant
    Filed: October 10, 1989
    Date of Patent: May 22, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Robert H. Bond, Ivan Pawlenko
  • Patent number: 4925407
    Abstract: Contacts comprising nickel and a glass-forming additive have electrical contact properties which render them suitable as replacements for gold contacts; disclosed contacts have low contact resistance even after prolonged exposure to an oxidizing ambient. The glass-forming additive is one or several of the elements boron, silicon, germanium, phosphorus, arsenic, antimony, or bismuth, and contacts are readily formed, e.g., as layers on substrates. A crystallographically disordered structure is produced in a contact surface layer at least upon exposure to an oxidizing ambient; alternatively, such desired structure can be produced by ion bombardment and even in the absence of glass-forming additives.
    Type: Grant
    Filed: January 30, 1986
    Date of Patent: May 15, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Joachim J. Hauser, John T. Plewes, Murray Robbins
  • Patent number: 4924480
    Abstract: In a private telecommunications network, a plurality of digital PBXs are interconnected via pairs of codecs. The codecs of each pair, or "tandem", are each operative to encode 64 kilobit/second (kbps) mu-law speech so as to compress it to 16 kbps speech for transmission to the other codec in the tandem. The latter is operative to thereafter decompress the 16 kbps speech back to 64 kbps. Each codec has a second mode of operation in which, rather than decode the encoded speech, it preserves the bits thereof in its own output signal. The codec transitions to this mode whenever it recognizes the presence of another codec on its high-bit-rate side of the connection. As a result, only one encoding/decoding cycle is performed across the connection, thereby minimizing the speech-coding-induced distortion and delay therein.
    Type: Grant
    Filed: March 11, 1988
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Steven L. Gay, Richard D. Gitlin, John Hartung
  • Patent number: 4924510
    Abstract: Method and apparatus for reducing call setup time for calls to Advanced 800 customers by eliminating one database query. (Toll charges for 800 calls are paid by the called customer.) In the prior art, a call to an Advanced 800 customer required accessing a Basic 800 database, then, using data obtained therefrom, accessing an Advanced 800 database. In accordance with this invention, a table of the most frequently called Advanced 800 numbers and the corresponding data normally obtained from the Basic 800 database is dynamically maintained in each roll switching system. When an 800 call is received at a toll switching system, the table is examined to see if the Advanced 800 service accessing data is stored therein. If so, the advanced 800 database is directly accessed without first accessing the Basic 800 database; if not, the call is processed as in the prior art, plus updating the table if the call is to an Advanced 800 customer.
    Type: Grant
    Filed: December 28, 1988
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventor: Van-Ban Le
  • Patent number: 4924464
    Abstract: The present invention relates techniques for bidirectionally converting between a first format comprising N concurrent serial bit streams and a second format comprising a parallel TDM bit stream of N words using an array of storage elements, each bit stream comprising M-bits per word. In operation, the N words of the input bit stream(s) are sequentially shifted in a predetermined direction into the array of storage elements so that the N words lie parallel to each other along a first axis of the array. During the last clock period of the N words, the data associated with the storage elements not lying on a predetermined diagonal of the array are transposed across the predteremined diagonal so that the N words lie parallel to each other along a second orthogonal axis of the array. The transposed words are then shifted out of the array in the predetermined direction to provide an output for the converted output.
    Type: Grant
    Filed: March 13, 1989
    Date of Patent: May 8, 1990
    Assignees: American Telephone and Telegraph Company, AT&T Bell Laboratories
    Inventor: Gerald A. Baylock
  • Patent number: 4923521
    Abstract: In a process for repairing electronic device packages, the problem of removing solder remnants on substrate bonding pads is solved by, first, etching a pattern in silicon and metallizing the pattern to make a silicon wick. The solder remnants on the bonding pads are melted, and the etched pattern of the silicon wick is brought into contact with the remnants to remove them by capillary action. It is often convenient to heat the silicon wick so that solder remnants melt when the wick is brought into contact with them.
    Type: Grant
    Filed: October 11, 1988
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Jay J. Liu, Y. H. Wong
  • Patent number: 4923561
    Abstract: In a vertical gradient freeze (VGF) process for growing a large crystal of a Group III-V compound semiconductor in a pyrolytic boron nitride crucible (11), a major part of the inner surface of the crucible is first oxidized to form a boric oxide layer (12).
    Type: Grant
    Filed: September 23, 1988
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Jim E. Chemans, Eric M. Monberg
  • Patent number: 4923271
    Abstract: An optical device is disclosed which provides wavelength multiplexing/demultiplexing utilizing a plurality of focusing Bragg reflectors. Each Bragg reflector includes a plurality of confocal (i.e., common foci) elliptical grating lines, with the exit/entrance ports of the input/output waveguides located at the foci of the ellipse. By virtue of the elliptical design, the signal propagating outward from the exit port of the input waveguide will be reflected by the appropriate Bragg reflector and focused into the entrance port of the appropriate output waveguide. When each Bragg reflector exhibits a different ellipticity, but shares one common focal point, optical multiplexing/demultiplexing may be achieved. Optical filtering may be achieved when all Bragg reflectors are designed to have common foci.
    Type: Grant
    Filed: March 28, 1989
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Charles H. Henry, Rudolf F. Kazarinov, Rodney C. Kistler, Kenneth J. Orlowsky, Yosi Shani, Aasmund S. Sudbo
  • Patent number: 4923564
    Abstract: An etching process is described for etching aluminum containing III-V semiconductor compounds. The etch solution contains dichromate ion in acid aqueous solution in which the acid is either phosphoric acid or sulfuric acid. The etch solution is highly selective in that it etches the aluminum containing III-V semiconductor compounds without etching significantly other III-V semiconductor compounds not containing aluminum exposed to the same etching solution. the etching process is extremely useful in fabricating a variety of III-V semiconductor devices including heterojunction bipolar transistors, heterojunction field effect transistors and self-enhanced electro optic devices.
    Type: Grant
    Filed: August 24, 1989
    Date of Patent: May 8, 1990
    Assignee: American Telephone and Telegraph Company
    Inventors: Jaya Bilakanti, Edward J. Laskowski
  • Patent number: 4924492
    Abstract: In a telephone local loop transmission arrangement, data is communicated from the customer premises to the central office utilizing a multi-dimensional, passband signal illustratively at 480 kb/s and 1.544 Mb/s.
    Type: Grant
    Filed: March 22, 1988
    Date of Patent: May 8, 1990
    Assignees: American Telephone and Telegraph Company, AT&T Information Systems, Inc.
    Inventors: Richard D. Gitlin, Sailesh K. Rao, Jean-Jacques Werner, Nicholas Zervos