Patents by Inventor Charles K. Sestok
Charles K. Sestok 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).
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Patent number: 10778498Abstract: A direct conversion wireless transmitter includes IQ mismatch pre-compensation using direct learning adaptation to adjust IQ pre-compensation filtering. Widely-linear IQ_mismatch pre-compensation filtering compensates for IQ mismatch in the TX analog chain, filtering of input data x(n) to provide pre-compensated data y(n) with a compensation image designed to interfere destructively with the IQ_mismatch image. A feedback receiver FBRX captures feedback data z(n) used for direct learning adaptation. DL adaptation adjusts IQ_mismatch filters, modeled as an x(n)_direct and complex conjugate x(n)_image transfer functions w1 and w2, including generating an adaptation error signal based on a difference between TX/FBRX-path delayed versions of x(n) and z(n), and can include estimation and compensation for TX/FBRX phase errors. DL adaptation adjusts the IQ pre-comp filters w1/w2 to minimize the adaptation error signal. Similar modeling can be used for IQ mismatch.Type: GrantFiled: September 25, 2018Date of Patent: September 15, 2020Assignee: TEXAS INSTRUMENTS INCORPORATEDInventor: Charles K. Sestok, IV
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Publication number: 20190097866Abstract: A direct conversion wireless transmitter includes IQ mismatch pre-compensation using direct learning adaptation to adjust IQ pre-compensation filtering. Widely-linear IQ_mismatch pre-compensation filtering compensates for IQ mismatch in the TX analog chain, filtering of input data x(n) to provide pre-compensated data y(n) with a compensation image designed to interfere destructively with the IQ_mismatch image. A feedback receiver FBRX captures feedback data z(n) used for direct learning adaptation. DL adaptation adjusts IQ_mismatch filters, modeled as an x(n)_direct and complex conjugate x(n)_image transfer functions w1 and w2, including generating an adaptation error signal based on a difference between TX/FBRX-path delayed versions of x(n) and z(n), and can include estimation and compensation for TX/FBRX phase errors. DL adaptation adjusts the IQ pre-comp filters w1/w2 to minimize the adaptation error signal. Similar modeling can be used for IQ mismatch.Type: ApplicationFiled: September 25, 2018Publication date: March 28, 2019Inventor: Charles K. Sestok, IV
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Patent number: 10097396Abstract: A direct conversion wireless transmitter includes IQ mismatch pre-compensation using direct learning adaptation to adjust IQ pre-compensation filtering. Widely-linear IQ_mismatch pre-compensation filtering compensates for IQ mismatch in the TX analog chain, filtering of input data x(n) to provide pre-compensated data y(n) with a compensation image designed to interfere destructively with the IQ_mismatch image. A feedback receiver FBRX captures feedback data z(n) used for direct learning adaptation. DL adaptation adjusts IQ_mismatch filters, modeled as an x(n)_direct and complex conjugate x(n)_image transfer functions w1 and w2, including generating an adaptation error signal based on a difference between TX/FBRX-path delayed versions of x(n) and z(n), and can include estimation and compensation for TX/FBRX phase errors. DL adaptation adjusts the IQ pre-comp filters w1/w2 to minimize the adaptation error signal. Similar modeling can be used for IQ mismatch.Type: GrantFiled: August 24, 2015Date of Patent: October 9, 2018Assignee: TEXAS INSTRUMENTS INCORPORATEDInventor: Charles K. Sestok, IV
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Patent number: 9654326Abstract: A direct conversion wireless transceiver is configured for TX/FBRX sequential QMC calibration (coefficient generation) using separate/shared PLLs. A TX LO drives upconversion, and an RX LO drives downconversion. TX/RX digital QMC compensators compensate for IQ mismatch (with optional DPD compensation), and QMC calibration is used to calibrate the TX/RX QMC filter coefficients based on a QMC calibration procedure. The TX LO signal source is a TX PLL, and the RX LO signal source is selectively the TX PLL or a separate FBRX PLL. A QMC controller performs QMC calibration to generate calibrated TX/FBRX QMC filter coefficients, including: disconnecting the TX PLL from, and connecting the FBRX PLL to, the RX LO; generating calibrated TX QMC filter coefficients; generating calibrated FBRX QMC filter coefficients; disconnecting the FBRX PLL from, and connecting the TX PLL to, the RX LO; generating re-calibrated FBRX QMC filter coefficients.Type: GrantFiled: April 7, 2016Date of Patent: May 16, 2017Assignee: TEXAS INSTRUMENTS INCORPORATEDInventors: Hunsoo Choo, Charles K. Sestok, IV
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Publication number: 20160234055Abstract: A direct conversion wireless transceiver is configured for TX/FBRX sequential QMC calibration (coefficient generation) using separate/shared PLLs. A TX LO drives upconversion, and an RX LO drives downconversion. TX/RX digital QMC compensators compensate for IQ mismatch (with optional DPD compensation), and QMC calibration is used to calibrate the TX/RX QMC filter coefficients based on a QMC calibration procedure. The TX LO signal source is a TX PLL, and the RX LO signal source is selectively the TX PLL or a separate FBRX PLL. A QMC controller performs QMC calibration to generate calibrated TX/FBRX QMC filter coefficients, including: disconnecting the TX PLL from, and connecting the FBRX PLL to, the RX LO; generating calibrated TX QMC filter coefficients; generating calibrated FBRX QMC filter coefficients; disconnecting the FBRX PLL from, and connecting the TX PLL to, the RX LO; generating re-calibrated FBRX QMC filter coefficients.Type: ApplicationFiled: April 7, 2016Publication date: August 11, 2016Inventors: Hunsoo Choo, Charles K. Sestok, IV
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Publication number: 20160056990Abstract: A direct conversion wireless transmitter includes IQ mismatch pre-compensation using direct learning adaptation to adjust IQ pre-compensation filtering. Widely-linear IQ_mismatch pre-compensation filtering compensates for IQ mismatch in the TX analog chain, filtering of input data x(n) to provide pre-compensated data y(n) with a compensation image designed to interfere destructively with the IQ_mismatch image. A feedback receiver FBRX captures feedback data z(n) used for direct learning adaptation. DL adaptation adjusts IQ_mismatch filters, modeled as an x(n)_direct and complex conjugate x(n)_image transfer functions w1 and w2, including generating an adaptation error signal based on a difference between TX/FBRX-path delayed versions of x(n) and z(n), and can include estimation and compensation for TX/FBRX phase errors. DL adaptation adjusts the IQ pre-comp filters w1/w2 to minimize the adaptation error signal. Similar modeling can be used for IQ mismatch.Type: ApplicationFiled: August 24, 2015Publication date: February 25, 2016Inventor: Charles K. Sestok, IV
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Publication number: 20160049984Abstract: A direct conversion wireless transceiver is configured for TX/FBRX sequential QMC calibration (coefficient generation) using separate/shared PLLs. A TX path includes a TX LO driving upconversion, and an FBRX path includes an RX LO driving downconversion. TX/RX digital compensators include TX/RX QMC compensators that perform QMC compensation to compensate for IQ mismatch based on TX/RX QMC filter coefficients, and QMC calibration to calibrate the TX/RX QMC filter coefficients based on a QMC calibration procedure. The TX LO signal source is a TX PLL, and the RX LO signal source is selectively the TX PLL or a separate RX PLL.Type: ApplicationFiled: August 10, 2015Publication date: February 18, 2016Inventors: Hunsoo Choo, Charles K. Sestok, IV
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Patent number: 8547260Abstract: Compressive sensing is an emerging field that attempts to prevent the losses associated with data compression and improve efficiency overall, and compressive sensing looks to perform the compression before or during capture, before energy is wasted. Here, a reconstruction algorithm is proposed for a compressive sensing successive approximation register (SAR) analog-to-digital converter (ADC). Accordingly, an analog signal is converted to a first digital signal at a sampling frequency that is less than a Nyquist frequency for the analog signal, and a second digital signal is constructed from the first digital signal with a box constrained linear optimization process such that the second digital signal is approximately equal to an analog-to-digital conversion of the analog signal at the Nyquist frequency for the analog signal.Type: GrantFiled: September 16, 2011Date of Patent: October 1, 2013Assignee: Texas Instruments IncorporatedInventors: Charles K. Sestok, Andrew Waters
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Patent number: 8547258Abstract: A calibration method to compensate for a sparsifying basis mismatch is provided. An analog signal is converted to a first digital signal at a sampling frequency that is less than a Nyquist frequency for the analog signal to generate a first digital signal. Each of a plurality of spectral terms is iteratively isolated from the first digital signal, and the offset for each of the plurality of spectral terms is iteratively determined. A dictionary is then constructed using the offset for each of the plurality of spectral terms, where the dictionary compensates for mismatch from a sparsifying basis.Type: GrantFiled: December 12, 2011Date of Patent: October 1, 2013Assignee: Texas Instruments IncorporatedInventors: Charles K. Sestok, Andrew Waters
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Publication number: 20130147646Abstract: A calibration method to compensate for a sparsifying basis mismatch is provided. An analog signal is converted to a first digital signal at a sampling frequency that is less than a Nyquist frequency for the analog signal to generate a first digital signal. Each of a plurality of spectral terms is iteratively isolated from the first digital signal, and the offset for each of the plurality of spectral terms is iteratively determined. A dictionary is then constructed using the offset for each of the plurality of spectral terms, where the dictionary compensates for mismatch from a sparsifying basis.Type: ApplicationFiled: December 12, 2011Publication date: June 13, 2013Applicant: Texas Instruments IncorporatedInventors: Charles K. Sestok, Andrew Waters
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Patent number: 8406171Abstract: A coordinated multipoint transmitter is for use with a network MIMO super-cell and includes a coordination unit configured to provide joint link processing to coordinate a multipoint transmission corresponding to a set of transmission points. Additionally, the coordinated multipoint transmitter also includes a transmission unit configured to transmit the multipoint transmission using the set of transmission points. Additionally, a coordinated transmission receiver is for use with a network MIMO super-cell and includes a reception unit configured to receive a multipoint transmission corresponding to a set of transmission points. The coordinated transmission receiver also includes a processing unit configured to process the multipoint transmission from the set of transmission points.Type: GrantFiled: August 3, 2009Date of Patent: March 26, 2013Assignee: Texas Instruments IncorporatedInventors: Eko N. Onggosanusi, Runhua Chen, Il Han Kim, Badri N. Varadarajan, Anand G. Dabak, Charles K. Sestok
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Publication number: 20130069807Abstract: Compressive sensing is an emerging field that attempts to prevent the losses associated with data compression and improve efficiency overall, and compressive sensing looks to perform the compression before or during capture, before energy is wasted. Here, a reconstruction algorithm is proposed for a compressive sensing successive approximation register (SAR) analog-to-digital converter (ADC). Accordingly, an analog signal is converted to a first digital signal at a sampling frequency that is less than a Nyquist frequency for the analog signal, and a second digital signal is constructed from the first digital signal with a box constrained linear optimization process such that the second digital signal is approximately equal to an analog-to-digital conversion of the analog signal at the Nyquist frequency for the analog signal.Type: ApplicationFiled: September 16, 2011Publication date: March 21, 2013Applicant: Texas Instruments IncorporatedInventors: Charles K. Sestok, Andrew Waters
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Patent number: 8094050Abstract: With high speed, high resolution time-interleaved (TI) analog-to-digital converters (ADCs), bandwidth mismatches between the various ADC branches can pose a significant problem. Previously, though, no adequate solution has been found. Here, a method and apparatus are provided that can calculate and compensate for bandwidth mismatches in a TI ADC, enabling a high speed, high resolution TI ADC to be produced.Type: GrantFiled: February 22, 2011Date of Patent: January 10, 2012Assignee: Texas Instruments IncorporatedInventors: Charles K. Sestok, Fernando A. Mujica
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Publication number: 20110090107Abstract: Previously, when designing receivers for radio frequency (RF) or wireless communications, designers chose between time-interleaved (TI) analog-to-digital converters (ADCs) for intermediate frequency architectures and dual channel ADCs for direct conversion architectures. Here, similarities between TI ADCs and dual channel ADC were recognized, and an ADC that has the capability of operating as a TI ADCs and dual channel ADC is provided. This allows designer to have greatly increased flexibility during the design process which can greatly reduce design costs, while also allowing the manufacturer of the ADC to realize a reduction in its operating costs.Type: ApplicationFiled: October 15, 2009Publication date: April 21, 2011Applicant: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Charles K. Sestok, Zigang Yang
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Patent number: 7916051Abstract: With high speed, high resolution time-interleaved (TI) analog-to-digital converters (ADCs), bandwidth mismatches between the various ADC branches can pose a significant problem. Previously, though, no adequate solution has been found. Here, a method and apparatus are provided that can calculate and compensate for bandwidth mismatches in a TI ADC, enabling a high speed, high resolution TI ADC to be produced.Type: GrantFiled: October 2, 2009Date of Patent: March 29, 2011Assignee: Texas Instuments IncorporatedInventors: Charles K. Sestok, Fernando A. Mujica
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Patent number: 7916050Abstract: Previously, when designing receivers for radio frequency (RF) or wireless communications, designers chose between time-interleaved (TI) analog-to-digital converters (ADCs) for intermediate frequency architectures and dual channel ADCs for direct conversion architectures. Here, similarities between TI ADCs and dual channel ADC were recognized, and an ADC that has the capability of operating as a TI ADCs and dual channel ADC is provided. This allows designer to have greatly increased flexibility during the design process which can greatly reduce design costs, while also allowing the manufacturer of the ADC to realize a reduction in its operating costs.Type: GrantFiled: October 15, 2009Date of Patent: March 29, 2011Assignee: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Charles K. Sestok, Zigang Yang
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Publication number: 20100027456Abstract: A coordinated multipoint transmitter is for use with a network MIMO super-cell and includes a coordination unit configured to provide joint link processing to coordinate a multipoint transmission corresponding to a set of transmission points. Additionally, the coordinated multipoint transmitter also includes a transmission unit configured to transmit the multipoint transmission using the set of transmission points. Additionally, a coordinated transmission receiver is for use with a network MIMO super-cell and includes a reception unit configured to receive a multipoint transmission corresponding to a set of transmission points. The coordinated transmission receiver also includes a processing unit configured to process the multipoint transmission from the set of transmission points.Type: ApplicationFiled: August 3, 2009Publication date: February 4, 2010Applicant: Texas Instruments IncorporatedInventors: Eko N. Onggosanusi, Runhua Chen, Il Han Kim, Badri N. Varadarajan, Anand G. Dabak, Charles K. Sestok
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Patent number: 7394876Abstract: The present invention provides an enhanced channel estimator for use with an orthogonal frequency division multiplex (OFDM) receiver employing scattered pilot channel estimates. In one embodiment, the enhanced channel estimator includes a time interpolation estimator configured to provide time-interpolation channel estimates having at least one image for a portion of carriers having the scattered pilot channel estimates. The enhanced channel estimator also includes a frequency interpolation estimator coupled to the time interpolation estimator and configured to provide frequency-interpolation channel estimates for each carrier based on image suppression through balanced-error filtering.Type: GrantFiled: May 24, 2005Date of Patent: July 1, 2008Assignee: Texas Instruments IncorporatedInventors: Charles K. Sestok, IV, Anand G. Dabak, Jaiganesh Balakrishnan
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Patent number: 7031379Abstract: A method for deriving coefficients for a time domain equalizer function (24) as implemented by a digital signal processor (35) in a DSL modem (20) is disclosed. A transmitting modem (10), such as at a central office, issues a pseudo-random training sequence that is received by the receiving modem (20). Correlation matrices are derived by the digital signal processor (35), from which sets of eigenvalues and eigenvectors are derived. A flatness constraint on the frequency response of the time domain equalizer is established, and included with a flatness scaling factor (?) into a minimization cost function. One or more values of the flatness scaling factor (?), preferably between minimum and maximum eigenvalues, are evaluated in the cost function, to derive the optimum filter for the time-domain equalizer. The flatness constraint ensures that the time-domain equalizer is not subject to near null conditions and large variations in its frequency response.Type: GrantFiled: August 24, 2001Date of Patent: April 18, 2006Assignee: Texas Instruments IncorporatedInventors: Charles K. Sestok, IV, Nirmal C. Warke
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Publication number: 20030043894Abstract: A method for deriving coefficients for a time domain equalizer function (24) as implemented by a digital signal processor (35) in a DSL modem (20) is disclosed. A transmitting modem (10), such as at a central office, issues a pseudo-random training sequence that is received by the receiving modem (20). Correlation matrices are derived by the digital signal processor (35), from which sets of eigenvalues and eigenvectors are derived. A flatness constraint on the frequency response of the time domain equalizer is established, and included with a flatness scaling factor (&lgr;) into a minimization cost function. One or more values of the flatness scaling factor (&lgr;), preferably between minimum and maximum eigenvalues, are evaluated in the cost function, to derive the optimum filter for the time-domain equalizer. The flatness constraint ensures that the time-domain equalizer is not subject to near null conditions and large variations in its frequency response.Type: ApplicationFiled: August 24, 2001Publication date: March 6, 2003Inventors: Charles K. Sestok, Nirmal C. Warke