Patents Assigned to American Telephone & Telegraph Company
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Patent number: 5450249Abstract: A demodulator circuit receives an input signal read from a track of a magnetic medium and generates a control signal to maintain alignment of a read-write head with the track. The demodulator circuit includes at least one transistor. The at least one transistor has an electrode switchable between first and second voltage sources. The electrode is coupled to the second voltage source to block processing of the input signal. The electrode is coupled to the first voltage source to process the input signal. The at least one transistor provides an effective resistance when coupled to the first voltage source that is dependent on the voltage level of the first voltage source. The at least one transistor half-wave rectifies the input signal when the electrode is coupled to the first voltage source.Type: GrantFiled: May 19, 1993Date of Patent: September 12, 1995Assignee: American Telephone and Telegraph CompanyInventors: Krishnaswamy Nagaraj, Reza S. Shariatdoust
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Patent number: 5421930Abstract: A winding tool (14) is provided on a manipulator (18) of a type used to route the optical fiber. A hook (22) extends from the winding tool to capture optical fiber (10) extending from a device (11), and the hook is retracted to secure the fiber. A routing wheel (17) is positioned between the device (11 ) to which the optical fiber is connected and the reel such that the wheel can press the optical fiber (10) against an adhesive-coated substrate. The winding tool then winds the optical fiber around a reel (16). The optical fiber next feeds from the reel (16) to the routing wheel (17) as the manipulator (18) is moved to route the optical fiber on the coated substrate. Preferably, prior to the winding and wheel positioning step, the optical fiber between the reel and the routing wheel is engaged with an alignment tool (27).Type: GrantFiled: November 1, 1993Date of Patent: June 6, 1995Assignee: American Telephone and Telegraph CompanyInventor: William R. Holland
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Patent number: 5413884Abstract: A technique is disclosed for utilizing direct-write electron-beam photolithography and holographic optical exposure to form gratings in optoelectronic structures. The direct-write e-beam process is used to form rectangular grating teeth in a mask substrate, where the mask is then used as a phase mask to transfer the pattern to the optoelectronic device. Advantageously, the utilization of a direct write e-beam technique to form the grating pattern on the photomask allows for the formation of any desired number and location of abrupt phase shifts, multiple grating pitches, alignment fiducials, and any other desired features. Therefore, a single exposure of the direct write e-beam mask allows for a plurality of different grating patterns to be simultaneously printed.Type: GrantFiled: December 14, 1992Date of Patent: May 9, 1995Assignee: American Telephone and Telegraph CompanyInventors: Thomas L. Koch, Frederick W. Ostermayer, Jr., Donald M. Tennant, Jean-Marc Verdiell
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Patent number: 5361259Abstract: A WAN is formed using Frame Relay Protocol and a telephone network interface unit. An originating LAN sends a message to a router which communicates with a telephone network interface unit using Frame Relay Protocol. The telephone network interface unit determines the destination of a packet received from the router by interpreting the Frame Relay Protocol, and it associates a phone number with that destination. The interface unit uses the phone number to establish at least one DSO connection over a digital telephone network to a destination network interface. A destination network interface unit receives the packet from the digital telephone network and provides the packet to a router which interfaces to the destination LAN. The network interface units add or drop additional DSO channels as required by the traffic load and thereby provide variable bandwidth.Type: GrantFiled: February 19, 1993Date of Patent: November 1, 1994Assignee: American Telephone and Telegraph CompanyInventors: Steven D. Hunt, Edward W. Landis
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Patent number: 5230010Abstract: Fractional rate modulation is accomplished by separating incoming data into frames of bits. Each frame is partitioned into bit words of unequal lengths. The words are divided by a modulus to obtain remainders. The remainders are transmitted using for example QAM modulation. At the receiving end the process is reversed. The ratio of the baud rate of the system to the incoming bit rate defines the modulus as well as the number of QAM modulation points.Type: GrantFiled: September 26, 1990Date of Patent: July 20, 1993Assignee: American Telephone & Telegraph CompanyInventors: William L. Betts, Gordon F. Bremer
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Patent number: 5206317Abstract: Excellent resolution and sensitivity in the patterning of resists utilized in device and mask manufacture is obtained with a specific composition. In particular this composition involves polymers having recurring pendant acid labile .alpha.-alkoxyalkyl carboxylic acid ester moieties in the presence of an acid generator activated by actinic radiation such as UV-visible, deep ultraviolet, e-beam and x-ray radiation.Type: GrantFiled: April 10, 1990Date of Patent: April 27, 1993Assignees: E. I. du Pont de Nemours and Company, American Telephone and Telegraph CompanyInventors: Walter R. Hertler, Dotsevi Y. Sogah, Gary N. Taylor
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Patent number: 5194105Abstract: Apparatus (11) is robotically operated to pick up an optical element such as a ball lens (12) or an optical fiber, place it in a groove or depression (13) of a substrate (14), and apply pressure to it so that it is bonded to the substrate. The tool comprises a retracting element holder (17) surrounding a bonding tool (16). A vacuum channel (18) communicates with the element holder so that, by the application of a vacuum, it can pick up an optical element. The tool then moves the element to place it, for example, in a depression (13) of a substrate, whereupon the vacuum is released, thereby to allow the element to nest between opposing sidewalls of the depression. The retracting holder element is simultaneously retracted vertically upwardly so as to expose a bonding surface of the bonding tool. After the element has nested in the groove, the bonding tool contacts the element and forces it against opposite sidewalls to effect a thermo-compression bond of the optical element with the sidewalls.Type: GrantFiled: August 29, 1991Date of Patent: March 16, 1993Assignee: American Telephone and Telegraph CompanyInventor: Hung N. Nguyen
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Patent number: 5187763Abstract: An optical fiber cable (20) includes a core which (22) is filled with a filling material (26) comprising a composition of matter which passes industry wide drip tests, which substantially has no oil separation and which has excellent thermal oxidative stability. The filling composition includes a relatively high molecular weight aliphatic hydrocarbon which may be a polyalphaolefin, for example, or a relatively high molecular weight mineral oil. Also included in the composition of the filling material is a fumed silica, a block copolymer and a relatively high amount of an antioxidant system. Swelling of coating materials for optical fibers (25,25) which are relatively soft and which are in contact with the filling material is substantially less than that experienced with prior art filling materials. Because of the inclusion of a low pour point aliphatic hydrocarbon in the filling material, the cable provides excellent optical performance at low temperatures.Type: GrantFiled: April 26, 1991Date of Patent: February 16, 1993Assignee: American Telephone & Telegraph CompanyInventor: Ching-Fang Tu
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Patent number: 5164983Abstract: A telemarketing complex is managed by a system that compiles and processes traffic analysis data obtained from customer premises-based information sources as well as public switched telecommunications network-based information sources, such that service levels are automatically and dynamically balanced among telecommunications centers (TCs) in the complex. Typically, the telemarketing complex is comprised of a plurality of ACDs and a plurality of data centers that may be selectively linked to the (TCs) where the telemarketer receives calls. The system includes: (1) an interface to network-based services that report the origin and destination of each of a plurality of calls received by the telemarketer at all locations; (2) an interface to network-based services that enables the telemarketer to affect changes in call processing logic; and (3) a traffic control center processor (TCCP) that accepts input data from all other elements in the system.Type: GrantFiled: January 28, 1991Date of Patent: November 17, 1992Assignee: American Telephone & Telegraph CompanyInventors: Percy B. Brown, Brenda Casselman, Gerard Conn, Robert A. Malmi, Valentine C. Matula, Margaret H. Redberg, Dimitri T. Stein, Bernadette M. Strout
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Patent number: 5162792Abstract: An arrangement is provided to correlate random connections made at one end of a multiwire cable with connections that are to made at the opposite end of the cable, in which the different leads of the cable are usually separated, for example, by a distinctive color pattern. The arrangement includes identifying the respective leads by a distinguishing marking, connecting a first end of the leads to a first connector, sensing the distinguishing marking of the lead connected to each contact of the first connector, and, responsive to the first end distinguishing marking, generating a first order identifying signal.Type: GrantFiled: August 3, 1990Date of Patent: November 10, 1992Assignee: American Telephone and Telegraph CompanyInventor: Robert J. T. Morris
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Patent number: 5155788Abstract: A sheathed optical fiber (15) which may be used in a package (20) in guidance systems for tethered vehicles includes a carrier (21) on which are wrapped a plurality of convolutions of the sheathed optical fiber. The sheathed optical fiber in a preferred embodiment includes a metallic tubular member (40) with optical fiber (30) being disposed in a longitudinally extending passageway (42) of the tubular member and secured therein against unintended lateral disassociation with the tubular member in a manner which minimize microbending losses. The reinforced optical fiber has mechanical ruggedness and tensile load capability which render it ideal for use in tethered vehicles.Type: GrantFiled: August 29, 1990Date of Patent: October 13, 1992Assignee: American Telephone & Telegraph CompanyInventors: J. Thomas Chapin, Carl R. Taylor, Peter A. Woog
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Patent number: 5134480Abstract: Deinterlacing systems and methods useful with television and other interlaced data signals derive values for pixels on missing lines using best matching values for blocks of pixels through time-recursive comparison of current pixels block values with such values for prior frames of data and also with later frames. Noise propagation is attenuated by mixing of current interpolated pixel data and memory size efficiency is achieved by comparisons based on blocks of pixels, with the block size adjustable for data accuracy. Use of chrominance signal comparisons and reduced data rate coding techniques provide added capabilities to the deinterlacing systems and methods.Type: GrantFiled: August 31, 1990Date of Patent: July 28, 1992Assignees: The Trustees of Columbia University in the City of New York, American Telephone and Telegraph CompanyInventors: Feng-Ming Wang, Dimitris Anastassiou, Arun N. Netravali
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Patent number: 5081647Abstract: A method and apparatus for communicating a voice conversation over a single telephone channel using continuously variable level quadrature amplitude modulation establishes and maintains two totally independent communication paths, each near perfect in amplitude and phase with respect to frequency over a bandwidth suitable for communication of continuously variable amplitude pulses. These pulses may be representations of any suitable bandlimited analog signal. The method establishes almost flawless QAM channels (real, imaginary), then allows switching to continuously variable amplitude analog transmissions.Type: GrantFiled: January 6, 1989Date of Patent: January 14, 1992Assignee: American Telephone & Telegraph CompanyInventor: Gordon Bremer
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Patent number: 5076096Abstract: Various methods have been proposed for measuring the viscosity of thermosetting polymers. It has been found that these method are generally inaccurate. A test which avoids the inaccuracies of previous techniques is proposed. In this test the heated thermosetting resin is forced at a known flow rate through a runner and through a capillary tube at the end of the runner. By measuring the pressure differential across the capillary a meaningful measure of viscosity is obtained.Type: GrantFiled: January 25, 1989Date of Patent: December 31, 1991Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: Lee L. Blyler, Jr., Philip Hubbauer, Gerhard W. Poelzing, Richard C. Progelhof
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Patent number: 5064051Abstract: An apparatus (20) is provided for transferring articles (40--40) from a pickup position to a pickoff position and then to a dropoff position. The apparatus includes a pair of pickup arms (60--60) which are spaced apart to engage lugs (42--42) oppositely extending from an article to be transferred. As the transfer arms are caused to be moved rotatably, the article is transferred to the pickoff position whereat the lugs are adjacent to stepped end portions (88--88) of a pair of pickoff arms (80--80). Further movement of the transfer arms causes the article to engage surfaces (92--92) of the stepped free ends of the pickoff arms and to be supported by engagement of the lugs with surfaces (94--94) of the stepped end portions of the pickoff arms. Afterwards, the pickoff arms are turned to allow the article to descend until, at a predetermined position, the lugs of the article become engaged with a conveyor (100) and become disengaged from the pickoff arms.Type: GrantFiled: July 24, 1990Date of Patent: November 12, 1991Assignee: American Telephone and Telegraph CompanyInventor: Robert F. Blundy
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Patent number: 5049721Abstract: A laser marking apparatus provides markings of enhanced readability in an outer jacket of repetitively spaced sections along the length of a moving cable which is delivered from a supply source. The cable is advanced under tension and is wound onto a take-up spool. The outer jacket is of a specified color and has an outer surface. The laser marking apparatus includes a first guide roller, a laser marker, an applicator, a coarse brush roller with a first driving mechanism, a fine brush roller with a second driving mechanism and a second guide roller. The first and second guide rollers are disposed adjacent to the supply source before the laser marker and before the take-up spool after the fine brush roller, respectively, in order to guide the cable along a path of travel so that the outer jacket passes adjacent to the laser marker. The laser marker inscribes in the outer jacket markings opening to the outer surface thereof.Type: GrantFiled: June 20, 1990Date of Patent: September 17, 1991Assignees: American Telephone and Telegraph Company, Directed Energy, Inc.Inventors: Stanley J. Parnas, Leroy V. Sutter, Jr., Randy C. Horne, Robert A. Wessels, Jr., Celestino Rey, Jack E. Andrews
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Patent number: H1137Abstract: A process for forming a dielectrically isolated wafer is disclosed. In particular, the conventional process is altered to replace the step of growing the thick polysilicon handle layer with the steps of growing a relatively thin conformal coating layer and bonding a single crystal wafer thereto. The wafer will become the substrate of the final device structure. The process of bonding is considered to be more efficient and economical than the prior art polysilicon growth process. Additionally, the tub structures of the wafer bonding process may be exposed to a somewhat lower temperature (for bonding) for shorter period of time than the tub regions of the conventional thick polysilicon DI structures. Therefore, the tub regions will exhibit superior qualities (e.g., less stress, fewer crystal defects) when compared with those formed with the conventional polysilicon growth technique.Type: GrantFiled: November 5, 1990Date of Patent: February 2, 1993Assignee: American Telephone and Telegraph CompanyInventors: William G. Easter, Richard H. Shanaman, III
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Patent number: H1155Abstract: An optical isolator is disclosed which comprises a Faraday rotator disposed between a pair of polarization selective elements (e.g., linear polarizers, birefringent wedges, birefringent plates, etc.). Improvement in isolation stability as a function of variations in temperature and/or signal wavelength are achieved in accordance with the teachings of the present invention by utilizing a Faraday device with a rotation .theta. less than the conventional 45.degree.. A linear reduction in .theta., while resulting in a some signal loss, provides a linear increase in both temperature and wavelength stability.Type: GrantFiled: June 8, 1992Date of Patent: March 2, 1993Assignee: American Telephone and Telegraph CompanyInventors: Vincent J. Fratello, Ralph S. Jameson, Steven J. Licht
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Patent number: H1174Abstract: A process for forming a dielectrically isolated wafer is disclosed. In particular, the conventional process is altered to replace the step of growing the thick polysilicon handle layer with the steps of growing a relatively thin conformal coating layer and bonding a single crystal wafer thereto. The wafer will become the substrate of the final device structure. The process of bonding is considered to be more efficient and economical than the prior art polysilicon growth process. Additionally, the tub structures of the wafer bonding process may be exposed to a somewhat lower temperature (for bonding) for shorter period of time than the tub regions of the conventional thick polysilicon DI structures. Therefore, the tub regions will exhibit superior qualities (e.g., less stress, fewer crystal defects) when compared with those formed with the conventional polysilicon growth technique.Type: GrantFiled: August 7, 1991Date of Patent: April 6, 1993Assignee: American Telephone and Telegraph CompanyInventors: William G. Easter, Richard H. Shanaman, III
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Patent number: H1373Abstract: Apparatus and method are disclosed for providing the transfer of a semiconductor wafer from a first to a second location. The apparatus includes a transfer arm including a plurality of apertures to facilitate the attachment of a bowed wafer, without breakage or frontside contact, to the transfer arm. The size, number and location of the apertures may be determined in accordance with the size of the wafer, the amount of bow, as well as the type of bow (i.e., simple or complex). A plurality of flexible members may be disposed in a one-to-one relationship with the apertures and utilized to achieve a secure vacuum seal of the wafer to the transfer arm.Type: GrantFiled: April 6, 1992Date of Patent: November 1, 1994Assignee: American Telephone and Telegraph CompanyInventors: Christopher E. Durham, William J. Malriat, Allen R. Melcher, Randy J. Penn