Patents by Inventor Anand Anandakumar
Anand Anandakumar 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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Publication number: 20230412276Abstract: A calibration system comprises control circuitry and waveform capture circuitry. The control circuitry selects a first calibration waveform for input to a digital predistortion circuit of a transmitter. The capture circuitry captures a first waveform output by the transmitter in response to the first calibration waveform. The control circuitry compares the first calibration waveform to the captured first waveform. The control circuitry selects a first one of a plurality of mapping circuit configurations based on the result of the comparison, wherein the mapping circuit is configured to map outputs of a plurality of delay circuits among inputs of a plurality of filter taps. The control circuitry stores the one of the mapping circuit configurations in nonvolatile memory associated with the transmitter.Type: ApplicationFiled: July 25, 2023Publication date: December 21, 2023Applicant: Maxlinear, Inc.Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Patent number: 11711149Abstract: A calibration system comprises control circuitry and waveform capture circuitry. The control circuitry selects a first calibration waveform for input to a digital predistortion circuit of a transmitter. The capture circuitry captures a first waveform output by the transmitter in response to the first calibration waveform. The control circuitry compares the first calibration waveform to the captured first waveform. The control circuitry selects a first one of a plurality of mapping circuit configurations based on the result of the comparison, wherein the mapping circuit is configured to map outputs of a plurality of delay circuits among inputs of a plurality of filter taps. The control circuitry stores the one of the mapping circuit configurations in nonvolatile memory associated with the transmitter.Type: GrantFiled: April 9, 2019Date of Patent: July 25, 2023Assignee: MaxLinear, Inc.Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Patent number: 10826616Abstract: A system comprises a digital predistortion circuit comprising: a first quantity of delay circuits configured to delay a signal to be predistorted; a second quantity of filter tap circuits, wherein the second quantity is smaller than the first quantity; and a delay-to-filter-taps mapping circuit that is operable to map each output of a first subset of the delay circuits to a corresponding input of the filter tap circuits. The system may comprise circuitry operable to select which of the first quantity of delay circuits is in the first subset. The selection of which of the first quantity of delay circuits is in the first subset may be based on a temperature measurement. The digital predistortion circuit may comprise cross-term generation circuitry operable to generate cross-term signals corresponding to the cross products of multiple, differently-delayed versions of a signal input to the digital predistortion circuit.Type: GrantFiled: April 5, 2019Date of Patent: November 3, 2020Assignee: MaxLinear, Inc.Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Publication number: 20190312649Abstract: A system comprises a digital predistortion circuit comprising: a first quantity of delay circuits configured to delay a signal to be predistorted; a second quantity of filter tap circuits, wherein the second quantity is smaller than the first quantity; and a delay-to-filter-taps mapping circuit that is operable to map each output of a first subset of the delay circuits to a corresponding input of the filter tap circuits. The system may comprise circuitry operable to select which of the first quantity of delay circuits is in the first subset. The selection of which of the first quantity of delay circuits is in the first subset may be based on a temperature measurement. The digital predistortion circuit may comprise cross-term generation circuitry operable to generate cross-term signals corresponding to the cross products of multiple, differently-delayed versions of a signal input to the digital predistortion circuit.Type: ApplicationFiled: April 5, 2019Publication date: October 10, 2019Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Publication number: 20190312650Abstract: A calibration system comprises control circuitry and waveform capture circuitry. The control circuitry selects a first calibration waveform for input to a digital predistortion circuit of a transmitter. The capture circuitry captures a first waveform output by the transmitter in response to the first calibration waveform. The control circuitry compares the first calibration waveform to the captured first waveform. The control circuitry selects a first one of a plurality of mapping circuit configurations based on the result of the comparison, wherein the mapping circuit is configured to map outputs of a plurality of delay circuits among inputs of a plurality of filter taps. The control circuitry stores the one of the mapping circuit configurations in nonvolatile memory associated with the transmitter.Type: ApplicationFiled: April 9, 2019Publication date: October 10, 2019Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Patent number: 10425262Abstract: Methods and systems are provided for adaptive guard interval (GI) combining. A signal carrying a symbol that is preceded by a guard interval (GI) that includes a portion of the symbol may be received, and a portion of the GI that is free from inter-symbol interference (ISI) may be determined. Only a part of the ISI-free portion of the GI may be selected. The selected part of the ISI-free portion of the GI may be less than a whole of the ISI-free portion. The selection may be configured based on a parameter that is applied to a function used in extracting the symbol. The parameter may be a timing adjustment, relative to a start of the symbol, applied to the function when extracting the symbol. Only the part of the ISI-free portion of the GI may then be extracted and combined with a corresponding portion of the symbol.Type: GrantFiled: August 27, 2018Date of Patent: September 24, 2019Assignee: MAXLINEAR, INC.Inventors: Mingrui Zhu, Arun Kedambadi, Seung Chul Hong, Anand Anandakumar
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Patent number: 10404497Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where in is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an in-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.Type: GrantFiled: September 20, 2018Date of Patent: September 3, 2019Assignee: Maxlinear, Inc.Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Patent number: 10389449Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a predistortion module, a feedback subsystem, a transmit optical subsystem, and an external modulator. The predistortion module is operable to receive an input digital signal and modify the input digital signal to produce a digital predistorted signal. The transmit optical subsystem is operable to generate an optical signal from the digital predistorted signal. The modification of the input digital signal is dynamically controlled by the feedback subsystem according to one or more characteristics of the optical signal as determined by the feedback subsystem. The amplitude of the external modulator output is also dynamically controlled by the feedback subsystem.Type: GrantFiled: September 19, 2018Date of Patent: August 20, 2019Assignee: Maxlinear, Inc.Inventors: Curtis Ling, Anand Anandakumar, Ioannis Spyropoulos
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Patent number: 10349112Abstract: Methods and systems for multi-path video and network channels may comprise a communication device comprising a wideband tuner (WB) and a narrowband tuner (NB). A video channel and a network channel may be received in the WB when the device is operating in a first stage. A video channel and a network channel may be received in the WB and the network channel may also be received in the NB when the device is operating in a second stage. The network channel may be received in the NB when the device is operating in a third stage. The reception of the network channel from both the WB and NB may enable a continuous reception of the network channel in a transition between the first and third stages. The WB may be operable to receive a plurality of channels and the NB may be operable to receive a single channel.Type: GrantFiled: August 23, 2018Date of Patent: July 9, 2019Assignee: Maxlinear, Inc.Inventors: Anand Anandakumar, Sheng Ye, Curtis Ling
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Patent number: 10326462Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.Type: GrantFiled: October 8, 2018Date of Patent: June 18, 2019Assignee: Maxlinear, Inc.Inventors: Pawandeep Taluja, Mingrui Zhu, Xuefeng Chen, Anand Anandakumar, Sheng Ye, Timothy Gallagher
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Publication number: 20190123946Abstract: Methods and systems are provided for adaptive guard interval (GI) combining. A signal carrying a symbol that is preceded by a guard interval (GI) that includes a portion of the symbol may be received, and a portion of the GI that is free from inter-symbol interference (ISI) may be determined. Only a part of the ISI-free portion of the GI may be selected. The selected part of the ISI-free portion of the GI may be less than a whole of the ISI-free portion. The selection may be configured based on a parameter that is applied to a function used in extracting the symbol. The parameter may be a timing adjustment, relative to a start of the symbol, applied to the function when extracting the symbol. Only the part of the ISI-free portion of the GI may then be extracted and combined with a corresponding portion of the symbol.Type: ApplicationFiled: August 27, 2018Publication date: April 25, 2019Inventors: Mingrui Zhu, Arun Kedambadi, Seung Chul Hong, Anand Anandakumar
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Publication number: 20190068227Abstract: A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.Type: ApplicationFiled: October 26, 2018Publication date: February 28, 2019Inventors: Subramanian Anantharaman Chandrasekarapuram, Anand Anandakumar, Stephane Laurent-Michel, Sheng Ye, Raja Pullela, Glenn Chang, Vamsi Paidi
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Patent number: 10218459Abstract: Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.Type: GrantFiled: May 2, 2017Date of Patent: February 26, 2019Assignee: Maxlinear, Inc.Inventors: Seung-Chul Hong, Anand Anandakumar, Curtis Ling
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Publication number: 20190044525Abstract: Methods and systems for time interleaved analog-to-digital converter timing mismatch calibration and compensation may include receiving an analog signal on a chip, converting the analog signal to a digital signal utilizing a time interleaved analog-to-digital-converter (ADC), and reducing a blocker signal that is generated by timing offsets in the time interleaved ADC by estimating complex coupling coefficients between a desired digital output signal and the blocker signal utilizing a decorrelation algorithm on frequencies within a desired frequency bandwidth. The decorrelation algorithm may comprise a symmetric adaptive decorrelation algorithm. The received analog signal may be generated by a calibration tone generator on the chip. An aliased signal may be summed with an output signal from a multiplier. The complex coupling coefficients may be determined utilizing the decorrelation algorithm on the summed signals.Type: ApplicationFiled: October 8, 2018Publication date: February 7, 2019Inventors: Pawandeep Taluja, Mingrui Zhu, Xuefeng Chen, Anand Anandakumar, Sheng Ye, Timothy Gallagher
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Patent number: 10187096Abstract: A system comprises a microwave backhaul outdoor unit having a first resonant circuit, phase error determination circuitry, and phase error compensation circuitry. The first resonant circuit is operable to generate a first signal characterized by a first amount of phase noise and a first amount of temperature stability. The phase error determination circuitry is operable to generate a phase error signal indicative of phase error between the first signal and a second signal, wherein the second signal is characterized by a second amount of phase noise that is greater than the first amount of phase noise, and the second signal is characterized by a second amount of temperature instability that is less than the first amount of temperature instability. The phase error compensation circuitry is operable to adjust the phase of a data signal based on the phase error signal, the adjustment resulting in a phase compensated signal.Type: GrantFiled: May 31, 2017Date of Patent: January 22, 2019Assignee: Maxlinear, Inc.Inventors: Subramanian Anantharaman Chandrasekarapuram, Anand Anandakumar, Stephane Laurent-Michel, Sheng Ye, Raja Pullela, Glenn Chang, Vamsi Paidi
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Publication number: 20190020513Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where in is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an in-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.Type: ApplicationFiled: September 20, 2018Publication date: January 17, 2019Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Publication number: 20190013867Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a predistortion module, a feedback subsystem, a transmit optical subsystem, and an external modulator. The predistortion module is operable to receive an input digital signal and modify the input digital signal to produce a digital predistorted signal. The transmit optical subsystem is operable to generate an optical signal from the digital predistorted signal. The modification of the input digital signal is dynamically controlled by the feedback subsystem according to one or more characteristics of the optical signal as determined by the feedback subsystem. The amplitude of the external modulator output is also dynamically controlled by the feedback subsystem.Type: ApplicationFiled: September 19, 2018Publication date: January 10, 2019Inventors: Curtis Ling, Anand Anandakumar, Ioannis Spyropoulos
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Publication number: 20180367837Abstract: Methods and systems for multi-path video and network channels may comprise a communication device comprising a wideband tuner (WB) and a narrowband tuner (NB). A video channel and a network channel may be received in the WB when the device is operating in a first stage. A video channel and a network channel may be received in the WB and the network channel may also be received in the NB when the device is operating in a second stage. The network channel may be received in the NB when the device is operating in a third stage. The reception of the network channel from both the WB and NB may enable a continuous reception of the network channel in a transition between the first and third stages. The WB may be operable to receive a plurality of channels and the NB may be operable to receive a single channel.Type: ApplicationFiled: August 23, 2018Publication date: December 20, 2018Inventors: Anand Anandakumar, Sheng Ye, Curtis Ling
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Patent number: 10116469Abstract: An electronic receiver may generate a differential detection sequence based on a received symbol sequence and based on a m-symbol delayed version of the received symbol sequence, where m is an integer greater than 1. The particular differential detection sequence may be a result of an element-by-element multiplication of the particular received symbol sequence and the conjugate of an m-symbol delayed version of the particular received symbol sequence. The receiver may calculate differential decision metrics based on the differential detection sequence and based on a set of differential symbol sequences generated from the set of possible transmitted symbol sequences. The receiver may generate a decision as to which of a set of possible transmitted symbol sequences resulted in the received symbol sequence, where the decision is based on the differential decision metrics and the set of possible transmitted symbols sequences.Type: GrantFiled: December 13, 2017Date of Patent: October 30, 2018Assignee: Maxlinear, Inc.Inventors: Ioannis Spyropoulos, Anand Anandakumar
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Patent number: 10116390Abstract: Aspects of a method and system for feedback during optical communications are provided. In one embodiment, a system for optical communications comprises a predistortion module, a feedback subsystem, a transmit optical subsystem, and an external modulator. The predistortion module is operable to receive an input digital signal and modify the input digital signal to produce a digital predistorted signal. The transmit optical subsystem is operable to generate an optical signal from the digital predistorted signal. The modification of the input digital signal is dynamically controlled by the feedback subsystem according to one or more characteristics of the optical signal as determined by the feedback subsystem. The amplitude of the external modulator output is also dynamically controlled by the feedback subsystem.Type: GrantFiled: June 17, 2016Date of Patent: October 30, 2018Assignee: Maxlinear, Inc.Inventors: Curtis Ling, Anand Anandakumar, Ioannis Spyropoulos