Patents by Inventor Fernando A. Mujica
Fernando A. Mujica 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: 8311083Abstract: Conventional transceivers do provide some compensation for in-phase/quadrature (I/Q) imbalance. However, these techniques do not separately compensate for I/Q imbalance for the transmitter and receiver sides of the transceiver. Here, a transceiver is provided that allows for compensation of I/Q imbalance in the transmitter and receiver irrespective of the other to allow for a more accurate transceiver.Type: GrantFiled: December 29, 2009Date of Patent: November 13, 2012Assignee: Texas Instruments IncorporatedInventors: Lei Ding, Zigang Yang, Fernando Mujica, Roland Sperlich
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Patent number: 8306150Abstract: Systems and methods for identifying a transmission channel response and a feedback channel response from a plurality of composite system responses are disclosed. A plurality of shifted feedback signals are created by shifting a feedback signal frequency by a plurality of first offset values and/or by shifting a transmission signal frequency by a plurality of second offset values. The feedback signals are compared to an input signal to identify the transmission channel response and/or a feedback channel response. A control signal is generated for a pre-distortion circuit to modify the input signal by an inverse of the transmission channel response. The composite system response is measured at a plurality of operating frequencies and at the plurality of offset values. The measurements are stored in a matrix and singular value decomposition is applied to the matrix of measurements to calculate the transmission channel response and feedback channel response.Type: GrantFiled: June 25, 2010Date of Patent: November 6, 2012Assignee: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Carson A. Wick, Lei Ding, Milind Borkar, Roland Sperlich
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Publication number: 20120106211Abstract: Today, power distribution systems can be used to supply power to many loads, and since many loads, such as servers, are reactive (i.e., have capacitors and/or inductors), line distortion and power factor can be an issue. Conventional techniques to correct for line distortion and power factor use a specialized circuit that is generally in series with the load, but these specialized circuits can be prohibitively expensive when used in large numbers. Here, however, a corrective power supply has been provided, which can correct for other parallel power supplies that can reduce cost.Type: ApplicationFiled: November 3, 2010Publication date: May 3, 2012Applicant: Texas Instruments IncorporatedInventors: Marco Corsi, David Freeman, Fernando Mujica
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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: 20110317786Abstract: Systems and methods for identifying a transmission channel response and a feedback channel response from a plurality of composite system responses are disclosed. A plurality of shifted feedback signals are created by shifting a feedback signal frequency by a plurality of first offset values and/or by shifting a transmission signal frequency by a plurality of second offset values. The feedback signals are compared to an input signal to identify the transmission channel response and/or a feedback channel response. A control signal is generated for a pre-distortion circuit to modify the input signal by an inverse of the transmission channel response. The composite system response is measured at a plurality of operating frequencies and at the plurality of offset values. The measurements are stored in a matrix and singular value decomposition is applied to the matrix of measurements to calculate the transmission channel response and feedback channel response.Type: ApplicationFiled: June 25, 2010Publication date: December 29, 2011Applicant: TEXAS INSTRUMENTS INC.Inventors: Fernando A. Mujica, Carson A. Wick, Lei Ding, Milind Borkar, Roland Sperlich
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Publication number: 20110216851Abstract: Performing digital predistortion (DPD) for widely spaced narrowband signals, such as the signal used in multi-carrier GSM, can be very difficult. Here, a system is provided the performs DPD for widely spaced narrowband signals. In particular, this system uses a polynomial curve for values of a cross-correlation function (above a predetermined threshold) to determine a delay estimate, which allows for a more robust and accurate system.Type: ApplicationFiled: March 5, 2010Publication date: September 8, 2011Applicant: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Hardik P. Gandhi, Kun Shi
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Publication number: 20110158297Abstract: Conventional transceivers do provide some compensation for in-phase/quadrature (I/Q) imbalance. However, these techniques do not separately compensate for I/Q imbalance for the transmitter and receiver sides of the transceiver. Here, a transceiver is provided that allows for compensation of I/Q imbalance in the transmitter and receiver irrespective of the other to allow for a more accurate transceiver.Type: ApplicationFiled: December 29, 2009Publication date: June 30, 2011Applicant: Texas Instruments IncorporatedInventors: Lei Ding, Zigang Yang, Fernando Mujica, Roland Sperlich
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Publication number: 20110135034Abstract: Embodiments of the invention provide a DPD system where the transmit reference signal is transformed, including sub-sampling, frequency translation, and the like, to match the feedback signal, which goes thru a similar transformation process, to obtain an error signal. The same transformation is applied to a system model, which may be Jacobian, Hessian, Gradient, or the like, in an adaptation algorithm to minimize error.Type: ApplicationFiled: December 7, 2010Publication date: June 9, 2011Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Fernando A. Mujica, Lei Ding
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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: 20100246714Abstract: An apparatus and system are provided for crest factor reduction (CFR). Preferably, a peak from the wideband signal is detected. A gain from the magnitude of the peak and a threshold can then be calculated. Based on this information, each carrier's contribution to the peak can be approximated, and a cancellation pulse coefficient for each carrier from its contribution to the peak can be calculated. A base cancellation pulse can be calculated from the cancellation pulse coefficients for each carrier, and a cancellation pulse can be calculated from the base cancellation pulse and the gain, which can then be applied to the wideband signal.Type: ApplicationFiled: March 30, 2009Publication date: September 30, 2010Applicant: Texas Instruments IncorporatedInventors: Zigang Yang, Fernando A. Mujica, Gregory Copeland, Murtaza Ali
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Patent number: 7352823Abstract: Method for computing distances to received data points. A preferred embodiment comprises determining a first point on a grid nearest to the received point, computing a second point closest to the received point inside a specified area, wherein the second point is a point in a first coset, computing a third, fourth, and fifth point, wherein each point is a member of a different coset and each point is the closest point in its coset to the received point, and computing a distance from the received point to each of the second, third, fourth, and fifth points.Type: GrantFiled: December 30, 2003Date of Patent: April 1, 2008Assignee: Texas Instruments IncorporatedInventors: Udayan Dasgupta, Fernando A. Mujica, Murtaza Ali
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Patent number: 7342937Abstract: The present invention provides, in one embodiment, a method of simplifying filtering with respect to a band plan. The method includes selecting a reflection point relative to the band plan and designating subchannels as unusable within a filterable separation of the reflection point that would otherwise introduce an asymmetry within the filterable separation. The present invention also provides a filtering simplifier for use with a DSL system having a band plan. The filtering simplifier includes a reflection point selector configured to select a reflection point relative to the band plan. The filtering simplifier also includes a subchannel designator coupled to the reflection point selector and configured to designate subchannels as unusable within a filterable separation of the reflection point that would otherwise introduce an asymmetry within the filterable separation.Type: GrantFiled: March 2, 2005Date of Patent: March 11, 2008Assignee: Texas Instruments IncorporatedInventors: Arthur J. Redfern, Georgios Ginis, Fernando A. Mujica, Krista S. Jacobsen
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Patent number: 7298838Abstract: A method for reducing transmit echo in a DSL modem comprises selecting at least one cancellation device of a plurality of cancellation devices. An attenuation signal is generated using the selected cancellation device. At least a portion of transmit echo is removed from a receive signal using the attenuation signal.Type: GrantFiled: September 3, 2002Date of Patent: November 20, 2007Assignee: Texas Instruments IncorporatedInventors: Sandeep K. Oswal, Prakash Easwaran, Arijit Raychowdhury, Fernando A. Mujica
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Patent number: 7236532Abstract: A method of communicating across a channel includes receiving information having a known bandwidth and a known spectrum. The information is preferably in the form of a multicarrier modulated signal, e.g., a DMT signal. In one aspect, this information is received at a receiver having a reduced channel bandwidth. An aliasing spectrum can be calculated based on the known spectrum and the frequency difference between the known bandwidth and the reduced-channel bandwidth. The received information can then be modified based upon the aliasing function to compensate for alias distortion. For example, the received information can be modified by modifying the noise component or signal-to-noise ratio of the received information.Type: GrantFiled: June 11, 2001Date of Patent: June 26, 2007Assignee: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Michael O. Polley, Arthur J. Redfern, Nirmal C. Warke, Yaser M. Ibrahim
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Patent number: 7221754Abstract: A method is provided for accomplishing asymmetric digital subscriber loop classification and the design of passive hybrid networks for each of the classes. The resulting hybrids are suitable for implementation in a switchable hybrid architecture.Type: GrantFiled: February 1, 2003Date of Patent: May 22, 2007Assignee: Texas Instruments IncorporatedInventor: Fernando A. Mujica
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Patent number: 7130345Abstract: A number of basic equalization and demodulation structures have been shown to be appropriate for DMT systems depending on the channel, noise, and system parameters. These include single path, dual path, oversampled, and double rate structures. Using the fundamental computation units of two TEQs (FIR filters) and two FFTs, in conjunction with simple delays, downsampling and routing, single path, dual path, oversampled and double rate equalization structures can be realized from a common equalization structure.Type: GrantFiled: September 20, 2002Date of Patent: October 31, 2006Assignee: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Arthur John Redfern
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Patent number: 7123671Abstract: The present invention provides automatic gain control (AGC) for a wide variety of conditions encountered in DSL scenarios. In particular, the proposed AGC approach addresses the problem of analog front end saturation in which a plurality of gain stages (i.e., programmable gain amplifiers) and filter stages are interleaved with inaccessible intermediate points. The gain settings of each of the PGAs is increased (614) until the received signal exceeds a given threshold (620) or until the maximum setting for that PGA has been reached (624). If the current PGA setting has been maximized, the next PGA is considered (628) and the process is repeated until no additional gain is needed or until the available PGAs are exhausted. This process is iterated (630) with different maximum PGA settings for each iteration to enable a more uniform gain distribution.Type: GrantFiled: September 28, 2001Date of Patent: October 17, 2006Assignee: Texas Instruments IncorporatedInventor: Fernando A. Mujica
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Patent number: 7023929Abstract: A method of providing an improved transfer function for a Discrete Multitone (DMT) type modulation transmitter with digital filtering after modulation followed by digital to analog converter and analog filtering is provided by sending a test signal to said transmitter and measuring the results of the test signal to determine the transfer function. The inverse of the transfer function that needs to be compensated is determined and the inverse of transfer function to be compensated is truncated to the region of interest (H2). The desired band split component of pre-compensation filter is designed (H3). The desired target frequency response of the pre-compensation filter is determined by H4=H2*H3 where H4 is the multiplication of H2 and H3 Given the target frequency response in H4 Hermetian symmetry is imposed on the frequency response. The inverse Fourier transform (IFFT) is taken to generate a time domain filter, h5. The characteristic of this filter is added at the digital filtering after modulation.Type: GrantFiled: July 10, 2002Date of Patent: April 4, 2006Assignee: Texas Instruments IncorporatedInventors: Fernando A. Mujica, Udayan Dasgupta, Mangesh Sadafale, Sandeep Oswal, Prakash Easwaran