Patents by Inventor Andrew S. Wright
Andrew S. Wright has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 7295815Abstract: The invention is related to methods and apparatus for controlling and adapting a digital predistortion linearizer for amplification of bandlimited signals using non-linear amplifiers. The control method advantageously permits the predistortion function applied by a predistortion entity to provide a relatively constant gain. This attribute is advantageous for operation within cellular radio systems, which often employ digital power control systems. However, the disclosed techniques can also be applicable to virtually any type of digital predistortion for which an input signal or reference signal to be amplified is predistorted in a manner that is complementary to the distortion induced by a non-linear amplifier. Embodiments of the invention advantageously enhance the practicality of using digital linearization and predistortion amplification techniques.Type: GrantFiled: March 29, 2006Date of Patent: November 13, 2007Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Derek J. W. Ho, Bartholomeus T. W. Klijsen
-
Patent number: 7293055Abstract: A flexible adaptation engine includes a coefficient adaptation circuit that implements multiple adaptation algorithms, and/or multiple coefficient selection algorithms, to adapt the filter coefficients of one or more digital filters, such as the transversal filters of a receiver. In one embodiment, a controller selects the filter coefficients to be adapted, and the adaptation algorithm(s) to be used to adapt the selected coefficients, based on various criteria such as convergence status data, clock recovery status signals, the current load on a processor that adapts the coefficients, and/or manual control signals. In one embodiment, the architecture supports the ability to vary the number of coefficients that are updated at a time, and to concurrently apply different adaptation algorithms to different subsets of filter coefficients. The flexible adaptation engine may be implemented in application-specific hardware and/or as a processor that executes software.Type: GrantFiled: December 1, 2003Date of Patent: November 6, 2007Assignee: PMC-Sierra, Inc.Inventors: Matthew W. McAdam, Andrew S. Wright, Bill M. Lye
-
Patent number: 7260365Abstract: The invention is related to methods and apparatus for controlling and adapting a digital predistortion linearizer for amplification of bandlimited signals using non-linear amplifiers. The control method advantageously permits the predistortion function applied by a predistortion entity to provide a relatively constant gain. This attribute is advantageous for operation within cellular radio systems, which often employ digital power control systems. However, the disclosed techniques can also be applicable to virtually any type of digital predistortion for which an input signal or reference signal to be amplified is predistorted in a manner that is complementary to the distortion induced by a non-linear amplifier. Embodiments of the invention advantageously enhance the practicality of using digital linearization and predistortion amplification techniques.Type: GrantFiled: March 29, 2006Date of Patent: August 21, 2007Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Derek J. W. Ho, Bartholomeus T. W. Klijsen
-
Patent number: 7200367Abstract: The invention is related to methods and apparatus for controlling and adapting a digital predistortion linearizer for amplification of bandlimited signals using non-linear amplifiers. The control method advantageously permits the predistortion function applied by a predistortion entity to provide a relatively constant gain. This attribute is advantageous for operation within cellular radio systems, which often employ digital power control systems. However, the disclosed techniques can also be applicable to virtually any type of digital predistortion for which an input signal or reference signal to be amplified is predistorted in a manner that is complementary to the distortion induced by a non-linear amplifier. Embodiments of the invention advantageously enhance the practicality of using digital linearization and predistortion amplification techniques.Type: GrantFiled: March 29, 2006Date of Patent: April 3, 2007Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Derek J. W. Ho, Bartholomeus T. W. Klijsen
-
Patent number: 7177603Abstract: The invention is related to methods and apparatus for controlling and adapting a digital predistortion linearizer for amplification of bandlimited signals using non-linear amplifiers. The control method advantageously permits the predistortion function applied by a predistortion entity to provide a relatively constant gain. This attribute is advantageous for operation within cellular radio systems, which often employ digital power control systems. However, the disclosed techniques can also be applicable to virtually any type of digital predistortion for which an input signal or reference signal to be amplified is predistorted in a manner that is complementary to the distortion induced by a non-linear amplifier. Embodiments of the invention advantageously enhance the practicality of using digital linearization and predistortion amplification techniques.Type: GrantFiled: March 29, 2006Date of Patent: February 13, 2007Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Derek J. W. Ho, Bartholomeus T. W. Klijsen
-
Patent number: 7061990Abstract: The present invention is related to methods and apparatus that can advantageously reduce a peak to average signal level exhibited by single or by multicarrier multibearer waveforms. Embodiments of the invention further advantageously can manipulate the statistics of the waveform without expanding the spectral bandwidth of the allocated channels. Embodiments of the invention can be applied to either multiple carrier or single carrier systems to constrain an output signal within predetermined peak to average bounds. Advantageously, the techniques can be used to enhance the utilization of existing multicarrier RF transmitters, including those found in third generation cellular base stations. However, the peak to average power level managing techniques disclosed herein can apply to any band-limited communication system and any type of modulation. The techniques can apply to multiple signals and can apply to a wide variety of modulation schemes or combinations thereof.Type: GrantFiled: July 20, 2001Date of Patent: June 13, 2006Assignee: PMC-Sierra Inc.Inventors: Andrew S. Wright, Richard E. Ryan, Bartholomeus T. W. Klijsen, Denis John Peregrym, Brenda Davison
-
Patent number: 7061991Abstract: The present invention is related to methods and apparatus that can advantageously reduce a peak to average signal level exhibited by single or by multicarrier multibearer waveforms. Embodiments of the invention further advantageously can manipulate the statistics of the waveform without expanding the spectral bandwidth of the allocated channels. Embodiments of the invention can be applied to either multiple carrier or single carrier systems to constrain an output signal within predetermined peak to average bounds. Advantageously, the techniques can be used to enhance the utilization of existing multicarrier RF transmitters, including those found in third generation cellular base stations. However, the peak to average power level managing techniques disclosed herein can apply to any band-limited communication system and any type of modulation. The techniques can apply to multiple signals and can apply to a wide variety of modulation schemes or combinations thereof.Type: GrantFiled: July 20, 2001Date of Patent: June 13, 2006Assignee: PMC - Sierra Inc.Inventors: Andrew S. Wright, Richard E. Ryan, Bartholomeus T. W. Klijsen, Denis John Peregrym, Brenda Davison
-
Patent number: 7058369Abstract: The invention is related to methods and apparatus for controlling and adapting a digital predistortion linearizer for amplification of bandlimited signals using non-linear amplifiers. The control method advantageously permits the predistortion function applied by a predistortion entity to provide a relatively constant gain. This attribute is advantageous for operation within cellular radio systems, which often employ digital power control systems. However, the disclosed techniques can also be applicable to virtually any type of digital predistortion for which an input signal or reference signal to be amplified is predistorted in a manner that is complementary to the distortion induced by a non-linear amplifier. Embodiments of the invention advantageously enhance the practicality of using digital linearization and predistortion amplification techniques.Type: GrantFiled: November 21, 2002Date of Patent: June 6, 2006Assignee: PMC-Sierra Inc.Inventors: Andrew S. Wright, Derek J. W. Ho, Bartholomeus T. W. Klijsen
-
Patent number: 6973138Abstract: The present invention is related to methods and apparatus that advantageously permit the more efficient use of an input range of an analog-to-digital converter used by an adaptive predistortion linearized RF transmitter. A main signal component of a down-converted output of an RF transmitter is removed prior to the analog-to-digital conversion of the down-converted output, thereby allowing more of the input range of the analog-to-digital converter to capture an error signal component of the down-converted output. Embodiments of the present invention can thus adaptively tune the predistortion stage to a higher degree of linearity or can use lower cost analog-to-digital converters with fewer quantization steps for the same performance.Type: GrantFiled: January 18, 2001Date of Patent: December 6, 2005Assignee: PMC-Sierra, Inc.Inventor: Andrew S. Wright
-
Patent number: 6940916Abstract: The present invention is related to methods and apparatus that compensate for quadrature impairments of an analog quadrature modulator and/or demodulator over a relatively wide signal bandwidth. One embodiment pre-distorts baseband signals in a quadrature modulator compensation signal processor (QMCSP) to negate the quadrature impairment of an analog quadrature modulator and corrects a received baseband signal in a quadrature demodulator compensation signal processor (QDCSP) to cancel the quadrature impairment of an analog quadrature demodulator. The QMCSP and the QDCSP contain adaptive digital filter correction structures that pre-compensate and post-compensate, respectively, for the quadrature impairments introduced by the analog quadrature modulator and the analog quadrature demodulator over a relatively wide bandwidth.Type: GrantFiled: January 26, 2001Date of Patent: September 6, 2005Assignee: PMC-Sierra, Inc.Inventors: William Dean Warner, Soon Sun Shin, Andrew S. Wright
-
Publication number: 20040230187Abstract: In radiofrequency ablation, larger lesion volumes are obtained for a given energy delivery by energizing at least two electrodes on either side of the tumor so that current is focused between them rather than dispersed radially to a large area ground plate. Modified standard umbrella probes may be used or a specialized dual electrode array may be fabricated for simplified use. Differential impedance between tumor and non-tumor tissues at certain frequencies is exploited to further improve lesion shape and size.Type: ApplicationFiled: March 9, 2004Publication date: November 18, 2004Inventors: Fred T. Lee, Dieter Haemmerich, John G. Webster, Andrew S. Wright, Chris D. Johnson, David M. Mahvi
-
Publication number: 20040199559Abstract: A flexible adaptation engine includes a coefficient adaptation circuit that implements multiple adaptation algorithms, and/or multiple coefficient selection algorithms, to adapt the filter coefficients of one or more digital filters, such as the transversal filters of a receiver. In one embodiment, a controller selects the filter coefficients to be adapted, and the adaptation algorithm(s) to be used to adapt the selected coefficients, based on various criteria such as convergence status data, clock recovery status signals, the current load on a processor that adapts the coefficients, and/or manual control signals. In one embodiment, the architecture supports the ability to vary the number of coefficients that are updated at a time, and to concurrently apply different adaptation algorithms to different subsets of filter coefficients. The flexible adaptation engine may be implemented in application-specific hardware and/or as a processor that executes software.Type: ApplicationFiled: December 1, 2003Publication date: October 7, 2004Inventors: Matthew W. McAdam, Andrew S. Wright, Bill M. Lye
-
Patent number: 6798843Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.Type: GrantFiled: June 16, 2000Date of Patent: September 28, 2004Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Bartholomeus T. W. Klijsen, Paul V. Yee, Chun Yeung Kevin Hung, Steven J. Bennett
-
Patent number: 6771634Abstract: Registration attempts by a terminal using a contention protocol to communicate with a central system are controlled by transmitting a registration index from the central system to the terminal at specified temporal periods, and modifying the value of the registration index when the terminal should attempt to register with the central system. A mode flag is transmitted from the central system to the terminal at predetermined temporal intervals, and the value of the mode flag is modified when the central system is recovering from a disaster so that the terminal refrains from immediately attempting to register with the central system. During disaster recovery, the terminal is able to associate itself with one of a plurality of sub-intervals. The central system transmits a sub-interval designator to the terminal at regular temporal periods during disaster recovery. The central system modifies the value of the sub-interval designator after a predetermined number of the regular temporal periods.Type: GrantFiled: April 9, 1999Date of Patent: August 3, 2004Assignee: AT&T Wireless Services, Inc.Inventor: Andrew S. Wright
-
Patent number: 6697436Abstract: A predistortion system adaptively compensates for distortion introduced along one or more amplification chains of a power amplifier system. In one embodiment, the predistortion system includes a plurality of compensation circuits, each of which is coupled to, and configured to digitally predistort an input transmission signal to, a respective amplification chain of an antenna array system. Each such amplification chain has an output coupled to a respective antenna of the antenna array system. A processing unit monitors the input transmission signals to, and corresponding output signals from, each of the amplification chains on a time-shared basis, and generates updates to the compensation parameters used the corresponding compensation circuits.Type: GrantFiled: June 19, 2000Date of Patent: February 24, 2004Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Bartholomeus T. W. Klijsen, Paul V. Yee, Chun Yeung Kevin Hung, Steven J. Bennett
-
Patent number: 6587514Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM-AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.Type: GrantFiled: June 16, 2000Date of Patent: July 1, 2003Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Bartholomeus T. W. Klijsen, Paul V. Yee, Chun Yeung Kevin Hung, Steven J. Bennett
-
Patent number: 6570444Abstract: A digital predistortion amplifier design compensates for non-linear amplification of an input signal using predistortion techniques. The design provides a reduced noise floor by using separate digital to analog converters (DAC) to separately convert the input signal and an error correction signal. Furthermore, the input signal can be separated into two or more subbands of narrower bandwidth. Each of the subbands are converted to analog using a separate DAC. By reducing the power and/or bandwidth to be handled by any one DAC, the available levels of quantization of the DAC are applied to a lower power signal and therefore the signal to noise ratio resulting from the conversion process is improved. In addition, each digital subband is passed through a correction filter, which is driven by an adaptive control processing and compensation estimator to compensate for relative gain, phase, and delay inconsistencies between the different subbands.Type: GrantFiled: January 26, 2001Date of Patent: May 27, 2003Assignee: PMC-Sierra, Inc.Inventor: Andrew S. Wright
-
Patent number: 6476670Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM—AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.Type: GrantFiled: July 5, 2001Date of Patent: November 5, 2002Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Bartholomeus T. W. Klijsen, Paul V. Yee, Chun Yeung Kevin Hung, Steven J. Bennett
-
Publication number: 20020156472Abstract: Efficient ablation with multiple electrodes is obtained by rapidly switching electric power to the electrodes. In this way, shielding effects caused by the field around each electrode which would otherwise create cool spots, are avoided. Complex inter-electrode current flows are also avoided.Type: ApplicationFiled: June 10, 2002Publication date: October 24, 2002Inventors: Fred T. Lee, Dieter Haemmerich, John G. Webster, Andrew S. Wright, Chris D. Johnson, David M. Mahvi
-
Patent number: 6459334Abstract: A wideband predistortion system compensates for a nonlinear amplifier's frequency and time dependent AM—AM and AM-PM distortion characteristics. The system comprises a data structure in which each element stores a set of compensation parameters (preferably including FIR filter coefficients) for predistorting the wideband input transmission signal. The parameter sets are preferably indexed within the data structure according to multiple signal characteristics, such as instantaneous amplitude and integrated signal envelope, each of which corresponds to a respective dimension of the data structure. To predistort the input transmission signal, an addressing circuit digitally generates a set of data structure indices from the input transmission signal, and the indexed set of compensation parameters is loaded into a compensation circuit which digitally predistorts the input transmission signal.Type: GrantFiled: July 5, 2001Date of Patent: October 1, 2002Assignee: PMC-Sierra, Inc.Inventors: Andrew S. Wright, Bartholomeus T. W. Klijsen, Paul V. Yee, Chun Yeung Kevin Hung, Steven J. Bennett