Abstract: A system and method are provided for detecting and recovering from errors in a control store memory of an electronic data processing system. In some cases, errors in the control store memory are detected and recovered from without any required interaction with an operating system of the data processing system. Thus, errors in the control store memory can be handled seamlessly and efficiently, without requiring a maintenance technician, or in some cases, a specialized operating system routine, to help diagnose and fix the error.
Type:
Grant
Filed:
September 14, 2005
Date of Patent:
July 14, 2009
Assignee:
Unisys Corporation
Inventors:
Kenneth L. Engelbrecht, Douglas A. Fuller, David C. Johnson
Abstract: A laser structure (10, 60) and method of manufacturing a vertical-cavity surface-emitting laser (VCSEL). The laser structure (10, 60) is adapted to lase at a wavelength lambda and includes a first mirror stack (14), an active region (18) disposed on the first mirror stack (14) and a second mirror stack (22) disposed on the active region (18). The second mirror stack (22) includes a plurality of alternating mirror layer pairs (a, b) with a phase shifting region (24) disposed therein. The phase shifting region (24) is positioned outside the optical aperture (25) and away from the active region (18) by at least one mirror layer pair, with the optical thickness of the phase shifting region (24) being a multiple of one-fourth lambda, the phase shifting region (24) being oxidized reducing the reflectance of the second mirror stack (22) outside the aperture relative to inside the aperture.
Type:
Grant
Filed:
August 31, 1999
Date of Patent:
June 25, 2002
Assignee:
Honeywell Inc.
Inventors:
Ralph Herbert Johnson, James Gunter, Andrew Clark
Abstract: A load site voltage regulation control system. The load site receives electrical power from a utility over transmission lines. The load site also receives electrical power from a local generator unit operating with an inverter. The local generator unit and inverter arc coupled to the load by an EMI filter and a transformer. Voltage at the load is controlled by adjusting the inverter voltage using an inverter voltage command. The inverter voltage command is based on load voltage, inverter voltage, EMI filter voltage, utility supplied current, and inverter current. In one embodiment, the inverter voltage is adjusted to minimize utility supplied reactive and real power and to actively dampen EMI filter voltage, with the inverter voltage command being developed though a multi-loop PPI control system.
Abstract: A load site voltage regulation control system. The load site receives electrical power from a utility over transmission lines. The load site also receives electrical power from a local generator unit operating with an inverter. The local generator unit and inverter are coupled to the load by an EMI filter and a transformer. Voltage at the load is controlled by adjusting the inverter voltage using an inverter voltage command. The inverter voltage command is based on load voltage, inverter voltage, EMI filter voltage, utility supplied current, and inverter current. In one embodiment, the inverter voltage is adjusted to minimize utility supplied reactive and real power and to actively dampen EMI filter voltage, with the inverter voltage command being developed though a multi-loop PPI control system.