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公开(公告)号：US10680622B2
公开(公告)日：2020-06-09
申请号：US16143711
申请日：2018-09-27
Applicant: Silicon Laboratories Inc.
Inventor： Timothy A. Monk , Rajesh Thirugnanam
Abstract: A spur cancellation circuit uses low cost multipliers in a correlation circuit. Each low cost multiplier multiplies a value of a sense node by a representation of a sinusoid and supplies a multiplication result. A compare circuit compares the sinusoid to one or more threshold values and supplies a compare indication. A multiplexer selects between two or more inputs including a positive value of the sense node and a negative value of the sense node, based on the compare result. A single threshold at zero converts the sinusoid to a square wave and the multiplexer supplies either the positive value or the negative value, which is equivalent to multiplying the value at the sense node by 1 or −1 depending on the sign of the sinusoid. Two thresholds may be used to represent the sinusoid with three values, the positive value, the negative value, or zero.
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2.发明授权公开(公告)号：US10164643B2
公开(公告)日：2018-12-25
申请号：US15261239
申请日：2016-09-09
Applicant: Silicon Laboratories Inc.
Inventor： Srisai R. Seethamraju , Joseph D. Cali , Rajesh Thirugnanam , Richard J. Juhn
Abstract: Hysteresis causes the temperature dependent frequency characteristic of the crystal of a crystal oscillator to be different when the temperature is rising from a previous colder state and when the temperature is falling from a hotter state. A rising temperature-to-frequency mapping polynomial and a falling temperature-to-frequency mapping polynomial are generated and their evaluations are weighted based on a current temperature and past temperature(s). The weighted evaluations are combined and used in temperature-based frequency compensation of the crystal oscillator.
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公开(公告)号：US11095295B2
公开(公告)日：2021-08-17
申请号：US16018598
申请日：2018-06-26
Applicant: Silicon Laboratories Inc.
Inventor： Timothy A. Monk , Rajesh Thirugnanam
IPC: H03L7/093 , G01R29/26 , G04F10/00 , G01R31/317
Abstract: A spur measurement system uses a first device with a spur cancellation circuit that cancel spurs responsive to a frequency control word identifying a spurious tone of interest. A device under test generates a clock signal and supplies the clock signal to the first device through an optional divider. The spur cancellation circuit in the first device generates sine and cosine weights at the spurious tone of interest as part of the spur cancellation process. A first magnitude of the spurious tone in a phase-locked loop in the first device is determined according to the sine and cosine weights and a second magnitude of the spurious tone in the clock signal is determined by the first magnitude divided by gains associated with the first device.
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公开(公告)号：US20190393881A1
公开(公告)日：2019-12-26
申请号：US16018598
申请日：2018-06-26
Applicant: Silicon Laboratories Inc.
Inventor： Timothy A. Monk , Rajesh Thirugnanam
IPC: H03L7/093 , G04F10/00 , G01R31/317 , G01R29/26
Abstract: A spur measurement system uses a first device with a spur cancellation circuit that cancel spurs responsive to a frequency control word identifying a spurious tone of interest. A device under test generates a clock signal and supplies the clock signal to the first device through an optional divider. The spur cancellation circuit in the first device generates sine and cosine weights at the spurious tone of interest as part of the spur cancellation process. A first magnitude of the spurious tone in a phase-locked loop in the first device is determined according to the sine and cosine weights and a second magnitude of the spurious tone in the clock signal is determined by the first magnitude divided by gains associated with the first device.
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公开(公告)号：US20200106447A1
公开(公告)日：2020-04-02
申请号：US16143711
申请日：2018-09-27
Applicant: Silicon Laboratories Inc.
Inventor： Timothy A. Monk , Rajesh Thirugnanam
IPC: H03L7/085
Abstract: A spur cancellation circuit uses low cost multipliers in a correlation circuit. Each low cost multiplier multiplies a value of a sense node by a representation of a sinusoid and supplies a multiplication result. A compare circuit compares the sinusoid to one or more threshold values and supplies a compare indication. A multiplexer selects between two or more inputs including a positive value of the sense node and a negative value of the sense node, based on the compare result. A single threshold at zero converts the sinusoid to a square wave and the multiplexer supplies either the positive value or the negative value, which is equivalent to multiplying the value at the sense node by 1 or −1 depending on the sign of the sinusoid. Two thresholds may be used to represent the sinusoid with three values, the positive value, the negative value, or zero.
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Patent Agency Ranking
公开(公告)号：US09673833B1
公开(公告)日：2017-06-06
申请号：US15196707
申请日：2016-06-29
Applicant: Silicon Laboratories Inc.
Inventor： William J. Anker , Timothy A. Monk , Rajesh Thirugnanam
CPC classification number: H03M1/1023 , H03K3/0315 , H03M1/00 , H03M1/0624 , H03M1/12 , H03M1/56 , H03M1/60 , H03M2201/4233
Abstract: Two sets of information (phase and cycle count) that are created asynchronously in a voltage controlled oscillator based analog-to-digital converter. A third set of information is created that is a delayed cycle count. The three sets of information are used to determine the proper alignment of the phase and the cycle count.
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公开(公告)号：US10659060B2
公开(公告)日：2020-05-19
申请号：US16143717
申请日：2018-09-27
Applicant: Silicon Laboratories Inc.
Inventor： Timothy A. Monk , Rajesh Thirugnanam
Abstract: A spur cancellation circuit receives a target spur frequency indicative of a frequency of a spur to be canceled and supplies a spur cancellation signal based on the frequency. A frequency tracking circuit tracks a change in the frequency of the spur to be canceled based on a change in phase of the spur cancellation signal and generates an updated target spur frequency based on the change in the frequency of the spur.
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公开(公告)号：US10404209B2
公开(公告)日：2019-09-03
申请号：US15259897
申请日：2016-09-08
Applicant: Silicon Laboratories Inc.
Inventor： Joseph D. Cali , Rajesh Thirugnanam , Rahul Shukla , Srisai R. Seethamraju
Abstract: A temperature compensated crystal oscillator (TCXO) includes a crystal oscillator and a temperature sensor to provide a sensed temperature. A delay circuit has a selectable delay to delay the frequency compensation based on the sensed temperature. The delay compensates for a difference between when the temperature sensor reflects a change in temperature and when a frequency of a signal supplied by the crystal oscillator is affected by the change in temperature. The delay may be static or dynamic with respect to the current temperature sensed by the temperature sensor.
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9.发明申请公开(公告)号：US20180076819A1
公开(公告)日：2018-03-15
申请号：US15261239
申请日：2016-09-09
Applicant: Silicon Laboratories Inc.
Inventor： Srisai R. Seethamraju , Joseph D. Cali , Rajesh Thirugnanam , Richard J. Juhn
CPC classification number: H03L1/04 , H03B5/30 , H03L1/022 , H03L1/026 , H03L1/027 , H03L1/028 , H03L7/093 , H03L7/099 , H03L7/197
Abstract: Hysteresis causes the temperature dependent frequency characteristic of the crystal of a crystal oscillator to be different when the temperature is rising from a previous colder state and when the temperature is falling from a hotter state. A rising temperature-to-frequency mapping polynomial and a falling temperature-to-frequency mapping polynomial are generated and their evaluations are weighted based on a current temperature and past temperature(s). The weighted evaluations are combined and used in temperature-based frequency compensation of the crystal oscillator.
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公开(公告)号：US20180069553A1
公开(公告)日：2018-03-08
申请号：US15259897
申请日：2016-09-08
Applicant: Silicon Laboratories Inc.
Inventor： Joseph D. Cali , Rajesh Thirugnanam , Rahul Shukla , Srisai R. Seethamraju
CPC classification number: H03B5/32 , H03L1/027 , H03L7/1974
Abstract: A temperature compensated crystal oscillator (TCXO) includes a crystal oscillator and a temperature sensor to provide a sensed temperature. A delay circuit has a selectable delay to delay the frequency compensation based on the sensed temperature. The delay compensates for a difference between when the temperature sensor reflects a change in temperature and when a frequency of a signal supplied by the crystal oscillator is affected by the change in temperature. The delay may be static or dynamic with respect to the current temperature sensed by the temperature sensor.
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