Thomas B Endres

US Patent:

7180942, Feb 20, 2007

Filed:

Dec 20, 2002

Appl. No.:

10/327280

Inventors:

Wonzoo Chung - Renton WA, US
Thomas J. Endres - Seattle WA, US
Christopher D. Long - Maple Valley WA, US

Assignee:

Dotcast, Inc. - San Francisco CA

International Classification:

H03H 7/30
H03H 7/40
H03K 5/159

US Classification:

375233

Abstract:

The present invention uses a novel adaptive soft decision device in order to jointly optimize decision device and DFE operation. The soft decision device receives the input and output samples of the slicer and generates a feedback sample by non-linearly combining them with respect to a single decision reference parameter. Moreover, the soft decision device provides novel error terms used to adapt equalizer coefficients in order to jointly optimize decision device and equalizer coefficients.

US Patent:

7346105, Mar 18, 2008

Filed:

Apr 26, 2004

Appl. No.:

10/832102

Inventors:

Thomas J. Endres - Seattle WA, US
Douglas Whitcomb - Kent WA, US
Christopher David Long - Maple Valley WA, US
Wonzoo Chung - Kent WA, US

Assignee:

Dotcast, Inc. - Kent WA

International Classification:

H03H 7/30
H03H 7/40
H03K 5/159

US Classification:

375233, 375229, 375230, 375232, 375234, 375350

Abstract:

A decision feedback equalizer (DFE) architecture uses feedback samples that are over-sampled with respect to the symbol rate. On-baud feedback samples are quantized with a slicer, while off-baud samples are linear, IIR samples. Both forward and feedback filters are fractionally-spaced, but adapted only at the baud instances.

US Patent:

7349469, Mar 25, 2008

Filed:

Aug 7, 2002

Appl. No.:

10/213854

Inventors:

Thomas J. Endres - Kent WA, US
Haosong Fu - Levittown PA, US
Raúl A. Casas - Doylestown PA, US
Christopher H. Strolle - Fort Washington PA, US

Assignee:

ATI Research, Inc. - Santa Clara CA

International Classification:

H03H 7/30

US Classification:

375232

Abstract:

A single-axis receiver processes, for example, a complex vestigial sideband (VSB) modulated signal with an equalizer accounting for DC offset within the modulated signal. The DC offset embedded in a received signal may degrade the process of equalization. The equalizer includes a method of blind estimation of the DC offset for removing the DC offset. The estimate is generated by jointly minimizing a Constant Modulus (CM) cost function over equalizer parameters and a DC offset estimate. An arbitrary DC offset the CM cost function admits local spurious minima in terms of the equalizer function. If the DC offset at the receiver is equal to the DC offset inserted at the transmitter, which is equivalent to neglecting the ISI caused by the channel, then only half of the CM equalizer minima remain unchanged. Provided a power constraint on the signal space is satisfied, the DC offset estimate, computed with a joint optimization of the CM cost function, converges to the desired solution, and, thus, the equalizer parameters are guaranteed to converge to the desired solution.

US Patent:

7499501, Mar 3, 2009

Filed:

Apr 18, 2005

Appl. No.:

11/109464

Inventors:

Wonzoo Chung - Kent WA, US
Christopher D. Long - Maple Valley WA, US
Thomas J. Endres - Seattle WA, US

Assignee:

Omereen Wireless, LLC - Dover DE

International Classification:

H04B 1/38

US Classification:

375297, 4551143

Abstract:

Compensation methods and apparatus are disclosed for mitigating non-linear distortion of high power amplifiers used in communication transmitters, based on the minimization of the symbol error, in particular, for communication systems transmitting data embedded in existing co-channel signals. To overcome the difficulty of constructing pre-distortion mapping from the symbol error, an adaptive algorithm is disclosed to update compensation parameters for pre-distortion mapping. Another method exploits a test signal interval in the co-channel signal. During a known constant co-channel signal, distortion is estimated as a complex number and used to construct compensation parameters. The latter is further expanded by employing the adaptive algorithm for the non-test signal intervals.

US Patent:

7580455, Aug 25, 2009

Filed:

Mar 18, 2008

Appl. No.:

12/050834

Inventors:

Thomas J. Endres - Seattle WA, US
Douglas Whitcomb - Kent WA, US
Christopher David Long - Maple Valley WA, US
Wonzoo Chung - Kent WA, US

International Classification:

H03H 7/30
H03H 7/40
H03K 5/159

US Classification:

375233, 375229, 375230, 375232, 375350

Abstract:

A decision feedback equalizer (DFE) architecture uses feedback samples that are over-sampled with respect to the symbol rate. On-baud feedback samples are quantized with a slicer, while off-baud samples are linear, IIR samples. Both forward and feedback filters are fractionally-spaced, but adapted only at the baud instances.

US Patent:

7580482, Aug 25, 2009

Filed:

Feb 19, 2004

Appl. No.:

10/782316

Inventors:

Thomas J. Endres - Seattle WA, US
Christopher D. Long - Maple Valley WA, US
Wonzoo Chung - Kent WA, US
Rory Fagan - Mukilteo WA, US

International Classification:

H04L 27/00

US Classification:

375326, 375345

Abstract:

Various aspects and embodiments of the present invention derive statistics of received signal quality and use these statistics to jointly control operation of timing recovery, carrier recovery, automatic gain control, and equalization functions.

US Patent:

7853978, Dec 14, 2010

Filed:

Dec 9, 2005

Appl. No.:

11/299318

Inventors:

Thomas J. Endres - Seattle WA, US
Wonzoo Chung - Kent WA, US
Slobodan Simovich - San Francisco CA, US
W. Leo Hoarty - Morgan Hill CA, US

International Classification:

H04N 7/18

US Classification:

725 74, 725 85, 725135

Abstract:

Methods and apparatus for remote antenna subsystems that are physically isolated from receiver subsystems are disclosed. The communication between the two subsystems uses remote communication links. The remote communication links are either wireless, in which case they are designed for indoor low power communications, or are wired, using existing infrastructure in the household such as the power lines. Partitioning between the antenna and receiver subsystems is selectable.

US Patent:

RE42558, Jul 19, 2011

Filed:

Feb 20, 2009

Appl. No.:

12/390368

Inventors:

Wonzoo Chung - Kent WA, US
Thomas J. Endres - Seattle WA, US
Christopher D. Long - Maple Valley WA, US

Assignee:

Omereen Wireless, LLC - Dover DE

International Classification:

H03H 7/30
H03H 7/40
H03K 5/159

US Classification:

375233

Abstract:

The present invention uses a novel adaptive soft decision device in order to jointly optimize decision device and DFE operation. The soft decision device receives the input and output samples of the slicer and generates a feedback sample by non-linearly combining them with respect to a single decision reference parameter. Moreover, the soft decision device provides novel error terms used to adapt equalizer coefficients in order to jointly optimize decision device and equalizer coefficients.