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公开(公告)号：US11047890B2
公开(公告)日：2021-06-29
申请号：US16121259
申请日：2018-09-04
Inventor： Gautham S. Sivasankar , Tejasvi Das , Emmanuel Marchais , Amar Vellanki , Leyi Yin , John L. Melanson , Venugopal Choukinishi
IPC: G01R25/00 , H03D13/00 , H03F3/183 , H03G3/30 , H04R3/00 , H03G3/00 , G01R19/25 , G01R21/133 , G01R29/18 , G01R31/317 , G01R31/30 , G01R19/04
Abstract: A method of determining a phase misalignment between a first signal generated from a first signal path and a second signal generated from a second signal path may include obtaining multiple samples of the first signal proximate to when the first signal crosses zero wherein the first signal can be approximated as linear; obtaining multiple samples of the second signal proximate to when the second signal crosses zero wherein the first signal can be approximated as linear; based on the multiple samples of the first signal, approximating a first time at which the first signal crosses zero; based on the multiple samples of the second signal, approximating a second time at which the second signal crosses zero; and determining the phase misalignment between the first signal and the second signal based on a difference between the first time and the second time.
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公开(公告)号：US10976825B2
公开(公告)日：2021-04-13
申请号：US16660444
申请日：2019-10-22
Inventor： Tejasvi Das , Matthew Beardsworth , Michael Allan Kost , Gavin McVeigh , Hamid Sepehr , Carl L. Ståhl
Abstract: Embodiments described herein relate to methods and apparatuses for controlling an operation of a vibrational output system and/or an operation of an input sensor system, wherein the controller is for use in a device comprising the vibrational output system and the input sensor system. A controller comprises an input configured to receive an indication of activation or de-activation of an output of the vibrational output system; and an adjustment module configured to adjust the operation of the vibrational output system and/or the operation of the input sensor system based on the indication to reduce an interference expected to be caused by the output of the vibrational output system on the input sensory system.
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公开(公告)号：US10763811B2
公开(公告)日：2020-09-01
申请号：US16181762
申请日：2018-11-06
Inventor： Lei Zhu , Tejasvi Das , John L. Melanson , Wai-shun Wilson Shum , Jing Bai , Xin Zhao , Xiaofan Fei
Abstract: A system may include a digital modulator configured to modulate an input signal received at an input of the digital modulator to generate a modulated input signal at an output of the digital modulator, a digital gain element having a digital gain and coupled to the digital modulator, an open-loop Class-D amplifier coupled to an output of the digital modulator and configured to amplify the modulated input signal, wherein the open-loop Class-D amplifier is powered from a variable power supply having a variable supply voltage which is variable in response to one or more characteristics of the input signal, and a control circuit configured to control the digital gain to approximately cancel changes in an analog gain of the open-loop Class-D amplifier due to variation in the variable supply voltage in response to the one or more characteristics of the input signal.
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公开(公告)号：US10594310B2
公开(公告)日：2020-03-17
申请号：US16144104
申请日：2018-09-27
Inventor： Ku He , Tejasvi Das , Xin Zhao , Xiaofan Fei
Abstract: A method may include, in a system comprising a digital PWM subsystem having a tunable digital gain, a first path coupled to an output of the digital PWM subsystem and configured to drive an open-loop driver stage, and a second path coupled to the output of the digital PWM subsystem and configured to drive a closed-loop driver stage having a tunable analog gain: selecting one of the first path and the second path for processing an input signal to generate an output signal based on one or more characteristics of the input signal, setting the digital gain to a maximum digital gain and the analog gain to a minimum analog gain when the input signal is lesser than a first threshold, setting the digital gain to a minimum digital gain and the analog gain to a maximum analog gain when the input signal is greater than a second threshold magnitude, and varying the analog gain and the digital gain when the input signal is in a range greater than the first threshold and lesser than a second threshold.
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公开(公告)号：US20200058326A1
公开(公告)日：2020-02-20
申请号：US16103288
申请日：2018-08-14
Inventor： Ku He , Tejasvi Das , Xin Zhao , Xiaofan Fei
IPC: G11B27/034 , G11B27/19
Abstract: A polymorphic playback system is disclosed in which one or more parameters of a signal path of the polymorphic playback system are varied based on one or more characteristics of a playback signal processed by the signal path, wherein the polymorphic playback system may include a lower-latency detection filter, a higher-latency detection filter, and a control subsystem that uses the lower-latency detection filter for detecting the one or more first characteristics of the playback signal and uses the higher-latency detection filter for detecting the one or more second characteristics of the playback signal.
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Patent Agency Ranking
公开(公告)号：US10476444B1
公开(公告)日：2019-11-12
申请号：US16142498
申请日：2018-09-26
Inventor： Tejasvi Das , Xin Zhao , Ku He , Nishant Jain , Lei Zhu , Xiaofan Fei
Abstract: A system may include a plurality of playback paths comprising an open-loop playback path configured to drive an output load and a closed-loop playback path. The closed-loop playback path may include an outer feedback loop comprising one or more integrators, a quantizer, and an output driver for driving the output load, the outer feedback loop having an outer loop feedback gain and an inner feedback loop comprising the one or more integrators and the quantizer and excluding the output driver, wherein the inner feedback loop has a variable inner loop feedback gain which is adjustable to match the outer loop feedback gain.
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公开(公告)号：US10447217B2
公开(公告)日：2019-10-15
申请号：US15884912
申请日：2018-01-31
Inventor： Xin Zhao , Tejasvi Das , Xiaofan Fei , Alan Mark Morton
Abstract: An amplifier may include a first stage configured to receive an input signal at an amplifier input and generate an intermediate signal which is a function of the input signal, and a final output stage configured to generate an output signal which is a function of the intermediate signal at an amplifier output, and a signal feedback network coupled between the amplifier output and input. The final output stage may be switchable among a plurality of modes including at least a first mode in which the final output stage generates the output signal as a modulated output signal which is a function of the intermediate signal, and a second mode in which the final output stage generates the output signal as an unmodulated output signal which is a function of the intermediate signal. Structure of the feedback network and the first stage may remain static when switching between modes.
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公开(公告)号：US10321230B2
公开(公告)日：2019-06-11
申请号：US15482250
申请日：2017-04-07
Inventor： Tejasvi Das , Xin Zhao , Ku He , Xiaofan Fei
IPC: H04R3/00 , H03F99/00 , H03F1/02 , H03F3/21 , H03F3/217 , H03F3/30 , H03F3/72 , H03F3/185 , H04R29/00
Abstract: In accordance with embodiments of the present disclosure, a system may include a playback path and a control circuit. The playback path may have a playback input for receiving an input signal and configured to generate at a playback path output an output signal based on the input signal, wherein the playback path is configured to operate in a plurality of operational modes. The control circuit may be configured to receive a first signal from within the playback path and indicative of the input signal, receive a second signal generated from the input signal externally to the playback path, and select a selected operational mode from the plurality of operational modes based on the first signal and the second signal.
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公开(公告)号：US10263584B1
公开(公告)日：2019-04-16
申请号：US16133045
申请日：2018-09-17
Inventor： Tejasvi Das , Alan Mark Morton , Xin Zhao , Lei Zhu , Xiaofan Fei , Johann G. Gaboriau , John L. Melanson , Amar Vellanki
IPC: H03G3/30 , H03F3/187 , H04R3/00 , H03K17/687
Abstract: A system may include a digital pulse width modulator subsystem, a first path coupled to an output of the digital pulse width modulator subsystem, a second path coupled to the output of the digital pulse width modulator subsystem and configured to drive a closed-loop analog pulse width modulator, a controller to select between the first path and the second path for processing a signal based on one or more characteristics of the signal, wherein a first gain of the first path and a second gain of the second path are approximately equal at the time of switching selection between the first path and the second path or vice versa, in order to minimize artifacts due to the switching.
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公开(公告)号：US10116473B1
公开(公告)日：2018-10-30
申请号：US15926395
申请日：2018-03-20
Inventor： Pradeep Dhananjay , Tejasvi Das , Bhupendra Manola , Bruce E. Duewer
CPC classification number: H04L25/4927 , H03F1/0227 , H03F1/025 , H03F3/187 , H03F3/213 , H03F2200/03 , H03F2200/331 , H04B14/046 , H04L25/03159 , H04R3/04
Abstract: An apparatus may include a delta-sigma modulator for quantization noise shaping of a digital signal, a digital-to-analog converter configured to generate an analog signal from the digital signal, and an amplifier configured to amplify the analog signal and powered from a charge pump, wherein the charge pump is configured to operate at a switching frequency approximately equal to a zero of a modulator noise transfer function of the delta-sigma modulator, such that the impact of charge pump noise on a total harmonic distortion noise of the apparatus is minimized.
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