David Vernon Blackham

US Patent:

6396285, May 28, 2002

Filed:

Aug 14, 2000

Appl. No.:

09/638278

Inventors:

David VerNon Blackham - Santa Rosa CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01R 3500

US Classification:

324601, 324638

Abstract:

Method and apparatus to determine scattering coefficients for a device under test (DUT) using a vector network analyzer (VNA) is disclosed. Traditionally, for a DUT having P ports, all combinations of reflective and transmission coefficients are measured and calculated. This is true even for reciprocal devices where S =S because, during the measurement, the source and load matches vary. However, the present invention teaches that, for reciprocal devices, only one of the two transmission coefficients between a first port and a second port need be measured. Under the inventive technique, error terms are removed from the measured scattering coefficients. Then, the source and the load matches may be normalized to a normalization match value. The normalization process removes the differences of the source and the load matches. Accordingly, for reciprocal devices, only one of two reciprocal transmission coefficients need be measured to determine the transmission coefficients for both directions between the first and the second port.

US Patent:

6823276, Nov 23, 2004

Filed:

Apr 4, 2003

Appl. No.:

10/407671

Inventors:

David V. Blackham - Santa Rosa CA
Kenneth H. Wong - Santa Rosa CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01D 1800

US Classification:

702 85

Abstract:

A system and method are disclosed which provide for flexible and accurate test apparatus error value calculation. Error value calculation of a testing apparatus requires at least one unique measurement for each unknown error value using the equation that relates the measured response, the predicted response and the error value. When more equations than unknowns can be acquired, the system of equations is over-determined and an improvement of accuracy is possible, but accuracy may be lost when the predicted responses are not trusted to the same degree. The disclosed system and method provide the increased accuracy of an over-determined system, while accounting for predicted responses of varying degrees of trust.

US Patent:

6836743, Dec 28, 2004

Filed:

Oct 15, 2002

Appl. No.:

10/273015

Inventors:

David V. Blackham - Santa Rosa CA
Douglas K. Rytting - Santa Rosa CA

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G06F 1900

US Classification:

702107, 324601

Abstract:

A method and a vector network analyzer compensate for unequal source match and load match of a test port of the vector network analyzer. The method characterizes the source match and the load match, computes a delta-match factor from the characterized source match and load match, and uses the delta-match factor to compensate for the difference. The method compensates S-parameter data for a device under test measured by the vector network analyzer. The vector network analyzer comprises a computer program that, when executed by a controller, implements a calibration compensation.

US Patent:

6995571, Feb 7, 2006

Filed:

Jan 3, 2005

Appl. No.:

11/028161

Inventors:

James C. Liu - Santa Rosa CA, US
Kenneth H. Wong - Santa Rosa CA, US
David V. Blackham - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01R 35/00

US Classification:

324601, 324 7622

Abstract:

In one embodiment, a method comprises applying a stimulus signal to a reference frequency translation device (FTD) by a vector network analyzer during a calibration mode, wherein the reference FTD possesses equal conversion efficiency in forward and reverse directions and the reference FTD possesses unknown input and output reflection characteristics; measuring a response of the reference FTD; and determining forward and reverse transmission tracking error terms using data from the measured response and single-port error calibration terms.

US Patent:

7010443, Mar 7, 2006

Filed:

Oct 31, 2003

Appl. No.:

10/699526

Inventors:

Shigetsune Torin - Santa Rosa CA, US
Kenneth H. Wong - Santa Rosa CA, US
David VerNon Blackham - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01R 29/26

US Classification:

702 69, 324614

Abstract:

Noise power is measured within one or more designated frequency bands of an applied signal. The measurement includes frequency translating the applied signal by a set of equally spaced frequencies to form a corresponding set of intermediate frequency signals, measuring the noise in at least two measurement bands of each of the intermediate frequency signals that are separated by the frequency spacing of the equally spaced frequencies, and determining the noise power in the designated frequency band of the applied signal based on the noise measurements.

US Patent:

7019536, Mar 28, 2006

Filed:

Jan 3, 2005

Appl. No.:

11/028032

Inventors:

Keith F. Anderson - Santa Rosa CA, US
David V. Blackham - Santa Rosa CA, US
Brad R. Hokkanen - Windsor CA, US
Kenneth H. Wong - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01R 35/00

US Classification:

324601, 324 7622

Abstract:

In one embodiment, a method of calibrating a multi-port vector network analyzer (VNA) includes (i) performing two-port calibrations on pairs of ports to determine forward and reverse systematic error terms associated with each pair of ports, wherein the pairs of ports are selected such that each port's systematic error terms (directivity, source match, reflection tracking, and load match) are determined, (ii) generating a switch error correction matrix using data from the two-port calibrations, and (iii) performing unknown thru calibration for at least one pair of ports that was not utilized in step (i), wherein the unknown thru calibration comprises applying the switch error correction matrix to measurement data and determining transmission tracking error terms using the corrected measurement data.

US Patent:

7054780, May 30, 2006

Filed:

Sep 13, 2004

Appl. No.:

10/939861

Inventors:

Joel Dunsmore - Sebastopol CA, US
Doug Bender - Santa Rosa CA, US
David Blackham - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G06F 19/00

US Classification:

702117, 324763, 714100

Abstract:

In one embodiment, a method of operating a network analyzer, comprises applying a stimulus signal on at least one port of the network analyzer for provision to a device under test (DUT) within a test fixture coupled to the network analyzer; generating measurement data from the DUT in response to the stimulus signal on at least one port of the network analyzer; and generating an amplitude response of the DUT across a frequency range, wherein a port extension module of the network analyzer automatically applies loss compensation to the amplitude response in a manner that is non-linearly related to frequency according to at least one controllable parameter.

US Patent:

7061254, Jun 13, 2006

Filed:

May 12, 2005

Appl. No.:

11/127852

Inventors:

Robert Edward Shoulders - Santa Rosa CA, US
David VerNon Blackham - Santa Rosa CA, US
Kenneth H. Wong - Santa Rosa CA, US

Assignee:

Agilent Technologies, Inc. - Palo Alto CA

International Classification:

G01R 35/00

US Classification:

324601, 324638

Abstract:

A power calibration method for a multi-port vector network analyzer (VNA) performs a two-port S-parameter calibration between a pair of ports of the multi-port VNA, and performs a power calibration of one of the ports in the pair of ports. From the two-port S-parameter calibration and the power calibration at the one port, power can be determined at one or more ports of a device under test (DUT) coupled to the ports of the multi-port VNA.