Robert A Lewandowski

55594271, Sep 24, 1996

Apr 4, 1994

8/222156

Mark E. Hinds - Seattle WA
Robert J. Lewandowski - Seattle WA
Thomas P. Locke - Woodinville WA
Tzafrir Sheffer - Seattle WA

Fluke Corporation - Everett WA

G01R 3102

324 66

An instrument and method for the troubleshooting and verification of copper-wire local area network (LAN) cable systems provides a series of resistance and capacitance measurements between all possible wire pairs using a pair of switch matrices and a software method for evaluating the measurements which are stored in a two-dimensional matrix. The stored measurements are evaluated against predetermined figures of merit and the decision pattern in matrix form is compared to that of a known good LAN cable system. Error messages responsive to mismatches are generated and presented to the operator via a user interface. Near-end cross talk (NEXT) isolation is evaluated using a mathematically calculated differential capacitance technique. Error messages are generated responsive to difference capacitance values larger than a figure of merit correlated to an acceptable level of NEXT isolation.

48840351, Nov 28, 1989

May 15, 1989

7/351229

Steven P. Cok - Seattle WA
Robert J. Lewandowski - Seattle WA

John Fluke Mfg. Co. Inc. - Everett WA

H03K 906
H03D 1300

328133

A digital phase/frequency detector circuit in a phase locked loop comprises a logic gate interconnected with a pair of bistable devices clocked respectively by input and reference digital signals to generate a square wave having a duty ratio corresponding to the phase/frequency difference between the two signals. The duty ratio of the square wave sweeps repetitively between minimum and maximum values as the phase/frequency difference changes monotonically. The square wave is integrated to obtain a repetitive sawtooth. To increase the range, circuitry is provided to provide a constant level signal when the peak of a sawtooth is approached and to reset the bistable devices to provide a multiple of the earlier range.

52764150, Jan 4, 1994

Jun 18, 1992

7/900328

Robert J. Lewandowski - Seattle WA
Daniel G. Dow - Bellevue WA
Frederick J. Telewski - Woodinville WA

H01P 500

333260

A compact selectable AC/DC coaxial coupling having a cylindrical signal coupling capacitor disposed within a section of coaxial transmission line. Inner and outer plates of the capacitor are electrically connected to an external connector and the center conductor of the transmission line, respectively. A radially biased conductive collet or a conductive mesh axially disposed on the center conductor is biased into and out of contact with the inner plate of the capacitor to enable or disable DC coupling. Alternatively, a resilient contact member is displaced through an externally accessible actuating rod to connect the center conductor to the inner plate of the capacitor. The integral nature of these switching mechanisms within a coaxial environment provides both low insertion losses and continuous impedance matching.

48433322, Jun 27, 1989

Aug 17, 1987

7/105468

Steven P. Cok - Seattle WA
Robert J. Lewandowski - Seattle WA

H03K 513
H03K 522

328133

A digital phase/frequency detector circuit in a phase locked loop comprises a logic gate interconnected with a pair of bistable devices clocked respectively by input and reference digital signals to generate a square wave having a duty ratio corresponding to the phase/frequency difference between the two signals. The duty ratio of the square wave sweeps repetitively between minimum and maximum values as the phase/frequency difference changes monotonically. The square wave is integrated to obtain a repetitive sawtooth. To increase the range, circuitry is provided to provide a constant level signal when the peak of a sawtooth is approached and to reset the bistable devices to provide a multiple of the earlier range.

56296282, May 13, 1997

May 23, 1996

8/652767

Mark E. Hinds - Seattle WA
Robert J. Lewandowski - Seattle WA
Thomas P. Locke - Woodinville WA
Tzafrir Sheffer - Seattle WA

Fluke Corporation - Everett WA

G01R 2704

324628

An instrument and method for the troubleshooting and verification of copper-wire local area network (LAN) cable systems provides a series of resistance and capacitance measurements between all possible wire pairs using a pair of switch matrices and a software method for evaluating the measurements which are stored in a two-dimensional matrix. The stored measurements are evaluated against predetermined figures of merit and the decision pattern in matrix form is compared to that of a known good LAN cable system. Error messages responsive to mismatches are generated and presented to the operator via a user interface. Near-end cross talk (NEXT) isolation is evaluated using a mathematically calculated differential capacitance technique. Error messages are generated responsive to difference capacitance values larger than a figure of merit correlated to an acceptable level of NEXT isolation.