David Liu

US Patent:

6898846, May 31, 2005

Filed:

Aug 21, 2002

Appl. No.:

10/224639

Inventors:

David Liu - Gaithersburg MD, US
Chengping Zhang - Rockville MD, US
Michael T. Duignan - Washington DC, US

Assignee:

Potomac Photonics, Inc. - Lanham MD

International Classification:

H05K003/30

US Classification:

29832, 29830, 29833, 29852

Abstract:

A method for manufacturing a modular electrical circuit includes the steps of pre-manufacturing a plurality of components having fine features such as resistors, capacitors, inductances, and conductors formed on a dielectric substrate. The pre-manufactured components are laminated each to the other in a predetermined order. Each pre-manufactured component includes one or more electrical elements of the same type coupled each to the other by conducting lines. Each dielectric substrate includes through vias filled with the conductive material which serve for cross-coupling of the elements of neighboring components. Position of the passive elements, as well as conductive lines and through vias, are pre-designed to allow precise coordination between the elements of different components in the multi-layered modular electrical circuit.

US Patent:

7106598, Sep 12, 2006

Filed:

Jun 14, 2004

Appl. No.:

10/865807

Inventors:

David Liu - Gaithersburg MD, US
Chengping Zhang - Rockville MD, US
Michael T Duignan - Washington DC, US

Assignee:

Potomac Photonics, Inc. - Lanham MD

International Classification:

H05K 1/00
H05K 1/11
H05K 7/02

US Classification:

361766, 361811, 361761, 361793, 174262

Abstract:

A method for manufacturing a modular electrical circuit includes the steps of pre-manufacturing a plurality of components having fine features such as resistors, capacitors, inductances, and conductors formed on a dielectric substrate. The pre-manufactured components are laminated each to the other in a predetermined order. Each pre-manufactured component includes one or more electrical elements of the same type coupled each to the other by conducting lines. Each dielectric substrate includes through vias filled with the conductive material which serve for cross-coupling of the elements of neighboring components. Position of the passive elements, as well as conductive lines and through vias, are pre-designed to allow precise coordination between the elements of different components in the multi-layered modular electrical circuit.

US Patent:

8213800, Jul 3, 2012

Filed:

Jul 17, 2009

Appl. No.:

12/504899

Inventors:

David Hwa-Wei Liu - Herndon VA, US
James M. Hallam - Oswego IL, US

Assignee:

Tellabs Operations, Inc. - Naperville IL

International Classification:

H04B 10/00

US Classification:

398115, 398 72, 398141

Abstract:

A wireless communication network system includes a central office network, a plurality of cell sites, each for communicating wirelessly with external cellular phones within its transmission range, and a passive optical network (PON)-based wireless backhaul system that transfers communication information between the cell sites and the central office network. The PON-based wireless backhaul system further includes at least a source optical network terminal (ONT), an optical line terminal (OLT), and a quality of service (QoS) converter in each of the source ONT and OLT to allow for quality of service-enabled communication between the cell sites and the central office network via the PON-based wireless backhaul system.

US Patent:

8566460, Oct 22, 2013

Filed:

Sep 15, 2010

Appl. No.:

12/882424

Inventors:

David Hwa-Wei Liu - Herndon VA, US
Edward J. Krzyzanowski - Naperville IL, US
James M. Hallam - Oswego IL, US

Assignee:

Tellabs Operations, Inc. - Naperville IL

International Classification:

G06F 15/16

US Classification:

709228

Abstract:

A method and apparatus for establishing a network connection using a temporary Internet Protocol (“IP”) address are disclosed. The process, in one embodiment, is operable to detect link status from a link which is connected to a port of an access device. After identifying a link configuration from a set of predefined link configurations in accordance with the link status, an interface corresponding to the link configuration is enabled. Once a temporary IP address associated with the interface is assigned, the process sends a message indicating that the access device is reachable via the link in accordance with the temporary IP address.

US Patent:

20080278144, Nov 13, 2008

Filed:

May 9, 2007

Appl. No.:

11/746183

Inventors:

David Hwa-Wei Liu - Herndon VA, US

International Classification:

G01R 1/06

US Classification:

324149

Abstract:

An elongated, spring-biased, connector clip carries, at a distal end thereof, a plurality of electrical contacts. The clip can be used to access a plurality of terminals or contact points in an electrical unit which are not readily accessible. Distal ends of the clip are spring-biased to move toward one another so as to clamp the electrical terminals or contact points of interest. An open region is provided between the elongated fingers of the clip so that other electrical devices in the case can be avoided during insertion and use of the clip for diagnostic or test purposes.

US Patent:

20090016713, Jan 15, 2009

Filed:

Jul 13, 2007

Appl. No.:

11/777817

Inventors:

David H. Liu - Herndon VA, US
Guy M. Merritt - Purcellville VA, US
Brendan Mannix - Fairfax VA, US

Assignee:

Tellabs Vienna Inc. - Naperville IL

International Classification:

H04B 10/08

US Classification:

398 17

Abstract:

A method of detecting a problem in a communication network that supports at least one communication service communication service is provided. The method includes disconnecting a suspect component from the network, and replacing the suspect component with a diagnostic component configured to have the same network identification information as the suspect component. The method also includes determining if the problem still exists, and identifying the suspect component as defective if the problem no longer exists. In addition, the method includes identifying the problem as being caused by another part of the network besides the suspect component, if the problem still exists. An apparatus, system, and computer program are also provided for carrying out the method.

US Patent:

20090059933, Mar 5, 2009

Filed:

Aug 28, 2007

Appl. No.:

11/845908

Inventors:

David H. Liu - Herndon VA, US
John T. Burch - McLean VA, US
Charles E. Rothrauff - Sterling VA, US
Guy M. Merritt - Purcellville VA, US

Assignee:

Tellabs Vienna, Inc. - Naperville IL

International Classification:

H04L 12/56

US Classification:

370401

Abstract:

A network terminal includes a bridge to interface the network terminal to a data channel linked to a central office, a first interface of a first type, and a second interface of a second type that is different from the first type of interface. A processor controls the network terminal to route data packets received via the first interface to the data channel via the bridge, when the network terminal is set to operate in a normal mode, and to route data packets received via the first interface to the second interface, when the network terminal is set to operate in a test mode. In an example embodiment, the first interface is an Ethernet interface and the second interface is a MoCA interface.

US Patent:

20090060496, Mar 5, 2009

Filed:

Aug 31, 2007

Appl. No.:

11/897958

Inventors:

David H. Liu - Herndon VA, US
Sreeram Venkataraman - Ashburn VA, US
Peter L. Randall - Centerville VA, US

International Classification:

H04B 10/08

US Classification:

398 17

Abstract:

In a passive optical network (PON), multiple optical network terminals (ONTS) transmit data to an optical line terminal (OLT) using a common optical wavelength and fiber optical media. Various components of the PON, including the OLT and ONT(s), can malfunction. Centralized techniques for maintaining or diagnosing fault conditions may be ineffective in large networks or in relatively small networks because of vast amounts of information and limited storage capacity for the information. Thus, fault conditions may occur and not be diagnosed due to lost or overwritten information. Therefore, a distributed approach based on information related to ranging of ONTs within the PON is employed in an example embodiment of the invention. This distributed approach can improve monitoring and diagnosis of fault conditions that may lead to instability of the PON.