Yongtao N Wang

US Patent:

8170507, May 1, 2012

Filed:

Oct 29, 2008

Appl. No.:

12/260832

Inventors:

Yongtao Wang - Plano TX, US
Khurram Waheed - Plano TX, US
Sameh S. Rezeq - Dallas TX, US
Jaimin Mehta - Plano TX, US
Prasad Srinivasan - Irving TX, US
Khurram Muhammad - Dallas TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04B 1/04

US Classification:

4551143, 375297

Abstract:

Predistortion methods and apparatus for transmitter linearization in a communication transceiver are disclosed. An example apparatus to linearize a digitally controlled pre-power amplifier included in a transmitter of a communication transceiver disclosed herein comprises a predistorter to predistort an input signal to be processed by the digitally controlled pre-power amplifier, a coupling path within the communication transceiver to couple an output of the digitally controlled pre-power amplifier to an input of a receiver included in the communication transceiver without enabling an output power amplifier stage of a multi-stage power amplifier coupled to an output of the digitally controlled pre-power amplifier, wherein no additional hardware components are required to implement the coupling path within the communication transceiver, and a predistortion evaluator comprising a predistortion calibrator and a predistortion compensator to process data demodulated by the receiver to generate and update predistortion values for use by the predistorter.

US Patent:

8428526, Apr 23, 2013

Filed:

Mar 17, 2008

Appl. No.:

12/049995

Inventors:

Yongtao Wang - Plano TX, US
Khurram Muhammad - Dallas TX, US

Assignee:

Texas Instruments Incorporated - Dallas TX

International Classification:

H04B 1/04
H04K 3/00

US Classification:

455126, 455306

Abstract:

A system and method for tuning baseband filters in wireless transceivers. A method comprises coupling a radio frequency (RF) signal generated by the wireless transmitter at an input of a wireless receiver, the RF signal having a desired frequency, measuring a magnitude of the coupled RF signal at an output of an analog-to-digital converter at an output of an analog baseband filter, wherein the magnitude is measured at the desired frequency, and adjusting a corner frequency of the analog baseband filter in response to the determining that the measured magnitude differs from a specified value.

US Patent:

20080129569, Jun 5, 2008

Filed:

Sep 28, 2007

Appl. No.:

11/863999

Inventors:

Khurram Muhammad - Dallas TX, US
Yongtao Wang - Plano TX, US
Imtinan Elahi - Richardson TX, US

International Classification:

H03M 1/12

US Classification:

341155

Abstract:

One embodiment of the invention includes a mixed-signal filter. The mixed-signal filter comprises an analog signal path configured to process a first analog signal and an analog-to-digital converter (ADC) configured to convert the processed first analog signal to a digital signal. The mixed-signal filter also comprises a programmable digital feedback filter configured to filter the digital signal and a digital-to-analog converter (DAC) configured to convert the filtered digital signal to a second analog signal. The mixed-signal filter further comprises a signal combiner configured to combine an analog input signal of the mixed-signal filter and the second analog signal to generate the first analog signal.

US Patent:

20100123466, May 20, 2010

Filed:

Nov 17, 2008

Appl. No.:

12/272008

Inventors:

Yongtao Wang - Plano TX, US
Khurram Muhammad - Dallas TX, US

International Classification:

G01R 27/02

US Classification:

324605

Abstract:

A system and method for corner frequency compensation in a wireless receiver. A method comprises computing a corner frequency of a filter, and determining if the computed corner frequency is different from a desired corner frequency by less than a threshold. The method further comprises if the computed corner frequency differs from the desired corner frequency by more than the threshold, adjusting parameters of the filter to alter the corner frequency, and repeating the computing and the determining. The method additionally comprises if the computed corner frequency differs from the desired corner frequency by less than the threshold, leaving the parameters of the filter unchanged. The computing uses a measured phase response of the filter at a frequency outside of a passband of the filter.

US Patent:

20120281787, Nov 8, 2012

Filed:

May 2, 2012

Appl. No.:

13/462717

Inventors:

Yongtao Wang - Austin TX, US
Curtis Ling - Carlsbad CA, US
Tim Gallagher - Carlsbad CA, US

International Classification:

H03K 9/00

US Classification:

375316

Abstract:

Methods and systems for I/Q mismatch calibration and compensation for wideband communication receivers may comprise receiving a plurality of radio frequency (RF) channels, downconverting the received plurality of received RF channels to baseband frequencies, determining and removing average in-phase (I) and quadrature (Q) gain and phase mismatch of the downconverted channels, determining a residual phase and amplitude tilt of the downconverted channels with removed average I and Q gain and phase mismatch, and compensating for said residual phase and amplitude tilt I and Q gain and phase mismatch of the downconverted channels. The determined phase tilt may be compensated utilizing a phase tilt correction filter, which may comprise one or more all-pass filters. The average I and Q gain and phase mismatch may be determined utilizing a blind source separation (BSS) estimation algorithm.