International Business Machines Corporation

Rudolf Eugene Rehquate

Thomas E Stammely

Edward J Bodette

Michael H Crowder

Edward Stanely Suffern

James Edward Hughes

Kenneth J Christensen

Jerry Dagher

Beymer Bevill, Jr

George Courtney Long, Jr

Francis Edward Noel, Jr

Edward N Dials

Russell S Padgett

Daniel Joseph Hunt

William Drummond Owsley

Jeffrey Matthew Stoltz

Frances E Noel

A Lamond Hodges

A method of mitigating EMI in an electronic device includes selecting a subset of surface-mount socket connectors on an electronic device to be connected with corresponding working plug connectors and connecting the working plug connectors with the selected subset of socket connectors by inserting the working plug connectors into the selected subset of socket connectors. The method further includes positioning a dummy plug in each of the unselected surface-mount socket connectors, the dummy plug comprising a flexible foam material configured to attenuate electromagnetic radiation by absorption and having a dummy plug profile generally matched to a socket profile of the corresponding socket connector.

Mitigating electromagnetic interference using dummy plugs

The average EMR emissions of an electronic device may be reduced by implementing an electrically-active modulated termination. For example, the impedance may be continuously varied at one or more termination locations between two metal substructures to cause a like variation in the amplitude of each component of the EMR. According to one approach, cyclically varying the electrical impedance with a period of less than the time interval over which the EMR is measured will result in a reduction in the average measured EMR.

Measurement and control of electromagnetic interference

A system and method for mitigating EMI in an electronic device rely on a set of foam dummy plugs specially configured for insertion into socket connectors according to connector type. The foam plugs have no electrical terminals or wiring, but are made from a foam composite material that attenuates electromagnetic radiation by absorption. The foam composite material includes a foam matrix and electrically conductive particles impregnated within the foam matrix. A handle may be unitarily formed with the foam plug. The handle may include a stamped through-hole, forming a ring, to facilitate insertion and removal of the dummy plugs by hand.

A cluster of processing systems is provided wherein each processing system is set to operate at a unique operating frequency. Each unique frequency is set to differ from each other by at least a predetermined frequency differential or bandwidth. When clustered, the radiated emissions will not add. Rather, the RF energy is distributed over the predetermined frequency bandwidth and in so doing achieve a reduction of measured RF energy at any singular frequency. By using RF energy dispersal in systems consisting of aggregated processing elements as subsystems, the need for special or additional RF shielding is precluded. Current design and manufacturing techniques can continue to be used. Thus, reducing the overall cost of implementing aggregated systems.

RF energy dispersal in systems consisting of aggregated computing elements as subsystems

A cluster of processing systems wherein each system is set to operate at a unique operating frequency. Each unique frequency is set to differ from each other by at least a predetermined frequency differential or bandwidth. When clustered, the radiated emissions will not add. Rather, the RF energy is distributed over the predetermined frequency bandwidth and in so doing achieve a reduction of measured RF energy at any singular frequency. By using RF energy dispersal in aggregate systems, the need for special or additional RF shielding is precluded. Current design and manufacturing techniques can continue to be used. Thus, reducing the overall cost of implementing aggregated systems.

A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port. In the port mode, the switching system connects the second winding of the first transformer to the receiver circuit in the port, and it connects the second winding of the second transformer to the transmitter circuit in the port. Each port of the multi-port LAN switch further includes a DC voltage source that is switchably connected to the first connection of the port through a first switch. Each port further includes a second switch that connects the second connection of the port to a DC return-path in a first position, and connects the second connection to the first connection when in a second position.

Multi-port LAN switch for a token-ring network

A slot-type processor and one or more cache modules are incorporated into a vertically oriented, multiple chip module (CM) that is mounted to a printed circuit board. The MCM operates at ultra high frequencies and very high temperatures. Each component of the MCM has a heatsink, a thermal plate, and a series of mounting clips and screws which combine to dissipate heat. The heatsinks and thermal plates generate most of the electromagnetic interference (EMI) since they are not attached or grounded to the board. A series of alignment posts extend from the board and are used to individually and slidably mount each of the components to the board. Each thermal plate is grounded to the posts with grounding clips. The clips maintain contact with the thermal plate through wiping elements. Additional pressure is applied to the wiping elements through a post retaining bracket. The components are fully seated and retained in position with retaining cams.

Electromechanical emissions grounding device for ultra high speed processors

A multi-port LAN switch is provided that enables attached network devices to both communicate directly and to insert into a token-ring network through an attached concentrator. Each port of the multi-port LAN switch has a first transformer, a second transformer, and a switching system. The first transformer has a first winding connected to a first connection of the port. The second transformer has a first winding connected to a second connection of the port. The switching system switches to a port mode or an adapter mode as a function of a mode signal transmitted to the port. In the adapter mode, the switching system connects a second winding of the first transformer to a transmitter circuit in the port, and its connects a second winding of the second transformer to a receiver circuit in the port. In the port mode, the switching system connects the second winding of the first transformer to the receiver circuit in the port, and it connects the second winding of the second transformer to the transmitter circuit in the port. Each port of the multi-port LAN switch further includes a DC voltage source that is switchably connected to the first connection of the port through a first switch. Each port further includes a second switch that connects the second connection of the port to a DC return-path in a first position, and connects the second connection to the first connection when in a second position.

A device which attaches multiple workstations, printers, computers or the like to a single lobe of a communications network includes a multistation access unit (MAU) with multiple ports and a voltage generator unit which generates a phantom current to activate a remote switch which allows one or more ports on the MAU to transmit or receive information from the communications network.

Growing community of inventors

Raleigh, NC, United States of America

Rudolf Eugene Rehquate