Thomas R Kuntz

US Patent:

6366621, Apr 2, 2002

Filed:

Nov 3, 1998

Appl. No.:

09/185218

Inventors:

Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H03D 124

US Classification:

375321, 329357

Abstract:

A method of estimating pilot signal phase embedded in a wideband digital signal modulating a RF signal that is down converted to an intermediate frequency and digitized includes the steps of summing a block of the signal samples for removing the modulation data and generating data values representative of vector locations of the pilot signal with each data value representing an angular rotation of the pilot signal vector, and calculating the phase of the pilot signal by determining the arc tangent of the data values. The method produces a computationally efficient narrow band filter generated at the pilot signal frequency by simple addition of the digital data values. The method is usable in a software based 8-VSB digital television demodulation system.

US Patent:

6366629, Apr 2, 2002

Filed:

Nov 3, 1998

Appl. No.:

09/185421

Inventors:

Xiaofen Chen - West Linn OR
Thomas L. Kuntz - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H04L 700

US Classification:

375355, 348 21

Abstract:

A method of estimating symbol timing phase and rate offsets of a sampled digitally modulated signal having repetitive symbol sync sequences includes the steps of estimating symbol sync sequence locations in a block of signal samples using a cross-correlation with a reference pattern of ideal symbol sync sequences. Signal samples within subranges defining the symbol sync sequences in the block of signal samples are filtered for removing intersymbol interference. An iterative process of cross-correlation of the filtered signal samples within the subranges using the reference pattern of ideal symbol sync sequences and an ideal symbol sync correction pattern generates timing phase and rate offset values that are used to derive filter coefficients for resampling the filtered signal samples within the subranges using an interpolating filter. The rate offset value is derived using a linear model and performing an optimal estimation. The iterative cross-correlation and resampling process continues until the rate of change of timing phase and rate offset values are minimized.

US Patent:

6384589, May 7, 2002

Filed:

Apr 4, 2001

Appl. No.:

09/826495

Inventors:

Linley F. Gumm - Beaverton OR
Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G01R 1320

US Classification:

324 7626

Abstract:

Reference frequency spur cancellation in a synthesized measurement receiver is achieved by determining for any given frequency to which the receiver is tuned a list of integer multipliers of the reference frequency that produce spurious signals in the receivers passband. For those values the amplitude and phase for each spurious signal is determined in the digital domain and subtracted from the digital signal from the receiver. The reference frequency is then offset slightly and the measurement repeated. The maximum values between each measurement are combined to produce a measurement for the input signal without spurious signals.

US Patent:

6671334, Dec 30, 2003

Filed:

Nov 3, 1998

Appl. No.:

09/185419

Inventors:

Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR
Nikhil M. Deshpande - Beaverton OR
Kyle L. Bernard - Tigard OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H04L 2706

US Classification:

375340, 375349

Abstract:

A measurement receiver demodulator has a first processing channel for producing a filtered signal sample output where the signal samples are processed through a transmission system receiver filter and a second processing channel producing an unfiltered signal sample output where the signal samples are not processed through the transmission system receiver filter. The first processing channel down converts digitally modulated IF signal samples and filters the down converted signal samples using a combined transmission system receiver filter and front end hardware compensation filter. A synchronizer produces timing phase and rate offset parameters that are applied to a resampling filter to synchronize the filtered signal samples to symbol instances of the symbol modulation. The filtered, time-aligned signal samples are scaled using a derived scaling factor. A pilot offset level, if present, is estimated and removed.

US Patent:

6741642, May 25, 2004

Filed:

Apr 3, 1998

Appl. No.:

09/055049

Inventors:

Kyle L. Bernard - Tigard OR
Xiaofen Chen - West Linn OR
Thomas L. Kuntz - Portland OR

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G06F 1100

US Classification:

375228

Abstract:

A modulation analyzer includes a smoothing processor which processes the coordinates of symbol landing points to generate a curve that optimally fits the landing points under a selected criterion.

US Patent:

6850238, Feb 1, 2005

Filed:

Jul 31, 2001

Appl. No.:

09/919690

Inventors:

Craig D. Bryant - Portland OR, US
Thomas L. Kuntz - Portland OR, US
Kathryn A. Engholm - Beaverton OR, US

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

G09G 522

US Classification:

3454401, 3454402, 382281, 375130, 370241, 702 60, 702 61, 702 68

Abstract:

A display of code power levels and relationships of multiple spreading factor orthogonal codes in a code division multiple access (CDMA) signal has a first code graph of code domain power (CDP) for all the codes at the largest code spreading factor that includes all codes at all spreading factors plotted in a linear code indexing order and a second graph of CDP where the codes are plotted in bit-reversed order to group together the sub-codes of each code of lower spreading factor. Markers on each graph are tied together such that movement of one marker on one graph to a particular code value causes the other marker on the other graph to move to the corresponding code value. The sub-codes related to a particular code bar in the graphs indicated by the markers may be differentiated by using grey scale or color variations. A base code power level indicator, which may be in the form of a horizontal bar on the bit-reversed order graph spanning the group of sub-codes corresponding to a particular spreading factor, provides a power indication for the base code.

US Patent:

7130328, Oct 31, 2006

Filed:

Aug 15, 2002

Appl. No.:

10/222092

Inventors:

Thomas L. Kuntz - Portland OR, US
Kathryn A. Engholm - Beaverton OR, US

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H04B 1/707
G01R 13/00

US Classification:

375140, 375224, 702 60, 702 67

Abstract:

A time history display of orthogonal code power levels by spreading factor is generated by displaying each data record of code domain power as a line, with each point in the line representing a different code index and the color or brightness of each data point representing the associated base code power level. With the data records displayed as contiguous lines, as each new data record is acquired it is added as a new line of the display while the line representing the oldest data record is deleted from the display. For communications standards where the code spreading factor varies, both bit-reversed and Walsh code graphs are displayed to show the grouping of the sub-codes that make up a base code. In this way the time history display indicates timing and trend information to a user.

US Patent:

8184608, May 22, 2012

Filed:

Mar 17, 2008

Appl. No.:

12/050103

Inventors:

Soraya J. Matos - Aloha OR, US
Thomas L. Kuntz - Portland OR, US
Thomas A. Elliot - Tigard OR, US
Jerry L. Young - Gresham OR, US

Assignee:

Tektronix, Inc. - Beaverton OR

International Classification:

H04B 7/216

US Classification:

370342, 34235763

Abstract:

A system and method is provided enabling identification of different PN offsets values for CDMA signals without access to a GPS signal, such as when making measurements within indoor environments. When a timing reference, such as that provided by a GPS signal, is lost, the frame boundary timestamp of the CDMA signal itself is used. The parameters of the strongest available PN offset are used. The timing error is determined and the new timing reference timestamp is estimated. The strongest PN is used as the time reference and tau is corrected for. In further embodiments, a user may be able to provide identifying information allowing the estimated timing reference timestamp to be determined even when a GPS signal was never established for providing an initial timing reference.