Patents Represented by Attorney, Agent or Law Firm Christopher J. Cianciolo
  • Patent number: 6744524
    Abstract: A method and apparatus is provided for calibrating a Fabry-Perot etalon based optical measurement system. The calibration is performed by analyzing the shape of transmission peaks output from the etalon in response to a known optical signal and using that information, along with a formula that approximates the response of the etalon, to perform the calibration.
    Type: Grant
    Filed: June 3, 2002
    Date of Patent: June 1, 2004
    Assignee: Nortel Networks Limited
    Inventors: Yakov Kogan, Reich L. Watterson, Donald L. McDaniel
  • Patent number: 6047357
    Abstract: A cache memory system includes multiple cache levels arranged in a hierarchical fashion. A data item stored in a higher level cache level is also stored in all lower level caches. The most recent version of a data item is detected during an initial lookup of a higher level cache. The initial lookup of a higher level cache includes a comparison of address bits for the next lower level cache. Thus the most recent version of a data item is able to be detected without additional lookups to the lower level cache.
    Type: Grant
    Filed: January 27, 1995
    Date of Patent: April 4, 2000
    Assignee: Digital Equipment Corporation
    Inventors: Peter J. Bannon, Elizabeth M. Cooper
  • Patent number: 5956478
    Abstract: A method for generating test cases for testing integrated circuits which comprises the step of apportioning a plurality of instructions into a plurality of groups of test instructions. At least some of the plurality of groups include a plurality of control flow instructions each of which transfer execution to a different one of the plurality of groups. This method prevents a test of an integrated circuit from entering an infinite loop.
    Type: Grant
    Filed: September 11, 1995
    Date of Patent: September 21, 1999
    Assignee: Digital Equipment Corporation
    Inventor: James Dwain Huggins
  • Patent number: 5933860
    Abstract: A computer system including an instruction cache (I-cache) having a plurality of banks for storing a subset of data from memory is shown to include a prediction mechanism for predicting which bank of the I-cache contains the required data. A prediction value, including a sequential prediction hint and a branch prediction hint, is associated with each instruction stored in the I-cache. The prediction value may either be stored with the I-cache data, or in a separate memory included before the I-cache. If the predicted value is incorrect, the predicted hint is `trained` to provide a higher degree of accuracy for repetitive instruction stream operation. Processor performance is additionally improved by providing a branch hint that allows for smoother transition between changing instruction streams.
    Type: Grant
    Filed: July 29, 1997
    Date of Patent: August 3, 1999
    Assignee: Digital Equipment Corporation
    Inventors: Joel S. Emer, Simon Steely, Edward J. McLellan
  • Patent number: 5847575
    Abstract: A driver circuit for limiting electrical noise on a quiescent signal is provided which includes a Transition High Driver circuit, a Transition Low Driver circuit, a Quiescent High Driver circuit, and a Quiescent Low Driver circuit. The driver circuit comprises means for driving an electrical signal with a presumed noisy Transition Power Supply network while it is transitioning from a low voltage level to a high voltage level or vice versa. The signal is driven by the Transition Power Supply network until the electrical signal reaches its quiescent voltage level. At this time, the signal is no longer driven by the Transition Power Supply network but rather by a presumed clean Quiescent Power Supply network. In this manner, noise from transitioning signals is prevented from coupling onto quiescent signals.
    Type: Grant
    Filed: June 21, 1996
    Date of Patent: December 8, 1998
    Assignee: Digital Equipment Corporation
    Inventors: Duane Galbi, Chris L. Houghton, John A. Kowaleski, Jr.
  • Patent number: 5822195
    Abstract: An interface module for an electronic system that permits signals to pass between a high frequency main circuit board area such as used for central processing units, memories, or other relatively high clock rate components and a low frequency circuit area such as used for standard peripheral circuit modules used for disk drives, video interfaces and the like. The interconnect module is positioned near an opening in a sheet metal bulkhead used as an electromagnetic interference (EMI) barrier around the main circuit area. The interface module uses a connector that is surrounded by one or more conductive shields that contain metal fingers on inboard and outboard sides to provide a ground connection between the interface module and the EMI barrier.
    Type: Grant
    Filed: March 31, 1997
    Date of Patent: October 13, 1998
    Assignee: Digital Equipment Corporation
    Inventors: Colin E. Brench, Stephen Richard Coe, Samuel Hammond Duncan, Stephen Edward Lindquist, Richard Ernest Olson
  • Patent number: 5802604
    Abstract: A method for translating a virtual address into a physical address, in which page tables used in the translation process are referenced by virtual addresses. Typically, a translation mechanism includes a translation buffer that, given a virtual address, can sometimes provide the corresponding physical address. A translation-buffer miss is said to occur when the translation buffer is presented with an address for which it can not provide the translation. When such a miss occurs, the translation mechanism obtains the translation by reading the page tables. When the translation mechanism attempts to read the page tables from virtual memory, a second-order miss can occur. The difficulty of infinite recursion of misses is avoided by handling second-order misses differently from first-order misses. When a second-order miss occurs, the translation mechanism uses a prototype page table entry and the virtual address of the page table entry to produce a physical address without using the page tables.
    Type: Grant
    Filed: July 19, 1993
    Date of Patent: September 1, 1998
    Assignee: Digital Equipment Corporation
    Inventors: Robert E. Stewart, Timothy Edwin Leonard, Sherry Tsi-chuan Lee
  • Patent number: 5788869
    Abstract: A method of etching a dielectric layer to form a via to an underlying conductive layer is described. The method includes etching selected portions of the dielectric using a plasma containing an etchant and monitoring electromagnetic energy of plasma emission radiation from the species to determine a ratio of a pair of the species in the plasma that is used to indicate the onset of an etch stop phenomenon. Etching of the dielectric continues and additional dielectrics are processed through the plasma etching step while the ratio of species is less than a predetermined threshold value. The process is stopped and a plasma reactor is cleaned once the ratio of the etchants exceeds the threshold value. The method can be used to form vias between a pair of conductive layers.
    Type: Grant
    Filed: November 2, 1995
    Date of Patent: August 4, 1998
    Assignee: Digital Equipment Corporation
    Inventors: Timothy J. Dalton, Ann C. Westerheim, Jamshed Hoshang Dubash, Marion Garver, Richard A. Bickford
  • Patent number: 5780897
    Abstract: An electrostatic discharge protection device for protecting a mixed voltage integrated circuit against damage is provided which includes at least one pair of NMOS transistors connected in a cascode configuration. Each NMOS transistor pair includes a first transistor, having a drain region coupled to an I/O stage of the mixed voltage integrated circuit, and a gate region coupled to the mixed voltage integrated circuit's low power supply. The protection device also includes a second NMOS transistor, merged into the same active area as the first transistor, having a gate region and source region coupled to the ground plane of the mixed voltage integrated circuit. The drain region of the second transistor and the source region of the first transistor is constructed by a shared NMOS diffusion region. This shared diffusion region also constructs the common node coupling the source region of the first transistor to the drain region of the second.
    Type: Grant
    Filed: November 13, 1995
    Date of Patent: July 14, 1998
    Assignee: Digital Equipment Corporation
    Inventor: David Benjamin Krakauer