Patents by Inventor Jonathan B. Ashbrook
Jonathan B. Ashbrook 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: 20180035181Abstract: An example embodiment includes a liquid crystal on silicon (LCOS) system. The LCOS system includes multiple pixels, a pixel voltage supply source (voltage source), an external buffer, and a local buffer. The voltage source is configured to supply an analog ramp to the pixels. The external buffer is configured to buffer the voltage source from the pixels. The local buffer is configured to buffer the external buffer from a subset of pixels of the plurality of pixels.Type: ApplicationFiled: June 12, 2017Publication date: February 1, 2018Inventors: Jonathan B. Ashbrook, Lionel Li, Brian R. Carey, Nicholas F. Jungels
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Patent number: 9767757Abstract: An example embodiment includes a LCOS IC. The LCOS IC includes multiple pixels, a column driver, and multiple conductive lines. The pixels are arranged in a pixel array. The column driver is configured to supply multiple signals to a column of pixels included in the pixel array. Each of the conductive lines couples the column driver to a subset of pixels in the column of pixels. The conductive lines are configured such that two or more of the signals can be supplied to two or more of the subsets of pixels with some overlapping duration.Type: GrantFiled: January 24, 2013Date of Patent: September 19, 2017Assignee: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Nicholas F. Jungels
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Patent number: 9681207Abstract: An example embodiment includes a liquid crystal on silicon (LCOS) system. The LCOS system includes multiple pixels, a pixel voltage supply source (voltage source), an external buffer, and a local buffer. The voltage source is configured to supply an analog ramp to the pixels. The external buffer is configured to buffer the voltage source from the pixels. The local buffer is configured to buffer the external buffer from a subset of pixels of the plurality of pixels.Type: GrantFiled: January 24, 2013Date of Patent: June 13, 2017Assignee: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Lionel Li, Brian R. Carey, Nicholas F. Jungels
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Patent number: 9310420Abstract: An example embodiment includes a continuity testing method of a pixel in a liquid crystal on silicon integrated circuit. The method includes writing a first voltage to a pixel. The pixel is isolated and a wire that is selectively coupled to the pixel is discharged. The method also includes enabling a sensing amplifier configured to sense voltage on the wire. The pixel is electrically coupled to the wire and a resultant voltage on the wire is sensed.Type: GrantFiled: January 24, 2013Date of Patent: April 12, 2016Assignee: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Lionel Li, Brian R. Carey
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Publication number: 20140204299Abstract: An example embodiment includes a liquid crystal on silicon (LCOS) system. The LCOS system includes multiple pixels, a pixel voltage supply source (voltage source), an external buffer, and a local buffer. The voltage source is configured to supply an analog ramp to the pixels. The external buffer is configured to buffer the voltage source from the pixels. The local buffer is configured to buffer the external buffer from a subset of pixels of the plurality of pixels.Type: ApplicationFiled: January 24, 2013Publication date: July 24, 2014Applicant: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Lionel Li, Brian R. Carey, Nicholas F. Jungels
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Publication number: 20140204330Abstract: An example embodiment includes a LCOS IC. The LCOS IC includes multiple pixels, a column driver, and multiple conductive lines. The pixels are arranged in a pixel array. The column driver is configured to supply multiple signals to a column of pixels included in the pixel array. Each of the conductive lines couples the column driver to a subset of pixels in the column of pixels. The conductive lines are configured such that two or more of the signals can be supplied to two or more of the subsets of pixels with some overlapping duration.Type: ApplicationFiled: January 24, 2013Publication date: July 24, 2014Applicant: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Nicholas F. Jungels
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Publication number: 20140204298Abstract: An example embodiment includes a continuity testing method of a pixel in a liquid crystal on silicon integrated circuit. The method includes writing a first voltage to a pixel. The pixel is isolated and a wire that is selectively coupled to the pixel is discharged. The method also includes enabling a sensing amplifier configured to sense voltage on the wire. The pixel is electrically coupled to the wire and a resultant voltage on the wire is sensed.Type: ApplicationFiled: January 24, 2013Publication date: July 24, 2014Applicant: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Lionel Li, Brian R. Carey
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Patent number: 8102938Abstract: A system and method is disclosed for controlling signal conditioning parameters and a sampling parameter controlling conversion of a received signal to digital sampled values prior to decoding. The sampled values are decoded according to a comparison with expected values calculated according to a model of a transmission channel. The model is also updated from time to time by comparing the expected values with actual sampled values. Variation of the expected values over time is calculated. One or more of the signal conditioning parameters and the sampling parameter are adjusted according to a numerical minimization method such that the system BER is reduced.Type: GrantFiled: April 22, 2008Date of Patent: January 24, 2012Assignee: Finisar CorporationInventors: Jonathan B. Ashbrook, Andrew C. Singer, Naresh R. Shanbhag, Robert J. Drost
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Patent number: 7834692Abstract: A peak detector circuit that responds rapidly to power transients, and yet is able to avoid interpreting data fluctuations as power transients by generating dual peak signals from an amplifier's differential output signal, where the dual peak signals have data ripple components that tend to cancel one another. The system and methods permit the peak detectors to be much more responsive to power transients by expanding their bandwidth (shortening the time constants) to the point that low frequency data components affect the individual peak detector signals, but the effects are cancelled out when the individual components are added together. The peak detector described herein may be used in an AGC system to provide ripple-free gain control signals, while rapidly following any power transients in transmitted signals.Type: GrantFiled: September 17, 2007Date of Patent: November 16, 2010Assignee: Finisar CorporationInventors: Hyeon Min Bae, Naresh Shanbhag, Jonathan B. Ashbrook
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Patent number: 7750831Abstract: Methods and systems are provided for an improved phase detector utilizing analog-to-digital converter (ADC) components. In an embodiment, the method includes from an ADC having a sampling clock signal that determines sampling instants, obtaining a first comparison value between an analog signal and a first threshold voltage at a first sampling instant, and obtaining a second comparison value between the analog signal and a second threshold voltage at a second sampling instant. The method further includes, from a supplemental circuit, obtaining a third comparison value between the analog signal and a third threshold voltage at a third sampling instant between the first and second sampling instants. The method further includes processing the first, second, and third comparison values to determine a phase relationship between the analog signal and the sampling clock.Type: GrantFiled: February 28, 2008Date of Patent: July 6, 2010Assignee: Finisar CorporationInventors: Heyon Min Bae, Naresh Ramnath Shanbhag, Andrew C. Singer, Jonathan B. Ashbrook
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Patent number: 7695085Abstract: A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.Type: GrantFiled: September 17, 2007Date of Patent: April 13, 2010Assignee: Finisar CorporationInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Jonathan B. Ashbrook
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Publication number: 20090262870Abstract: A system and method is disclosed for controlling signal conditioning parameters and a sampling parameter controlling conversion of a received signal to digital sampled values prior to decoding. The sampled values are decoded according to a comparison with expected values calculated according to a model of a transmission channel. The model is also updated from time to time by comparing the expected values with actual sampled values. Variation of the expected values over time is calculated. One or more of the signal conditioning parameters and the sampling parameter are adjusted according to a numerical minimization method such that the system BER is reduced.Type: ApplicationFiled: April 22, 2008Publication date: October 22, 2009Applicant: FINISAR CORPORATIONInventors: Jonathan B. Ashbrook, Andrew C. Singer, Naresh R. Shanbhag, Robert J. Drost
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Patent number: 7592869Abstract: An electronic amplifier circuit that provides improved gain control linearity characteristics resulting from having a controllable field effect transistor (FET) acting as a degeneration resistance (degeneration resistance FET) and a controllable load resistance FET. The overall gain function of the amplifier exhibits improved linearity in part due to the presence of the load FET, which tends to cancel the nonlinear behavior emanating from the degeneration FET. The circuit also includes a control circuit for generating non-linear control signals that are responsive to process characteristics of the FETs, such that the degeneration resistance FET and load resistance FETs may be controlled more consistently and independently from process variations.Type: GrantFiled: September 17, 2007Date of Patent: September 22, 2009Assignee: Finisar CorporationInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Jonathan B. Ashbrook
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Publication number: 20090219008Abstract: Methods and systems are provided for an improved phase detector utilizing analog-to-digital converter (ADC) components. In an embodiment, the method includes from an ADC having a sampling clock signal that determines sampling instants, obtaining a first comparison value between an analog signal and a first threshold voltage at a first sampling instant, and obtaining a second comparison value between the analog signal and a second threshold voltage at a second sampling instant. The method further includes, from a supplemental circuit, obtaining a third comparison value between the analog signal and a third threshold voltage at a third sampling instant between the first and second sampling instants. The method further includes processing the first, second, and third comparison values to determine a phase relationship between the analog signal and the sampling clock.Type: ApplicationFiled: February 28, 2008Publication date: September 3, 2009Applicant: FINISAR CORPORATIONInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Andrew C. Singer, Jonathan B. Ashbrook
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Publication number: 20090072865Abstract: A peak detector circuit that responds rapidly to power transients, and yet is able to avoid interpreting data fluctuations as power transients by generating dual peak signals from an amplifier's differential output signal, where the dual peak signals have data ripple components that tend to cancel one another. The system and methods permit the peak detectors to be much more responsive to power transients by expanding their bandwith (shortening the time constants) to the point that low frequency data components affect the individual peak detector signals, but the effects are cancelled out when the individual components are added together. The peak detector described herein may be used in an AGC system to provide ripple-free gain control signals, while rapidly following any power transients in transmitted signals.Type: ApplicationFiled: September 17, 2007Publication date: March 19, 2009Applicant: FINISAR CORPORATIONInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Jonathan B. Ashbrook
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Publication number: 20090072904Abstract: An electronic amplifier circuit that provides improved gain control linearity characteristics resulting from having a controllable field effect transistor (FET) acting as a degeneration resistance (degeneration resistance FET) and a controllable load resistance FET. The overall gain function of the amplifier exhibits improved linearity in part due to the presence of the load FET, which tends to cancel the nonlinear behavior emanating from the degeneration FET. The circuit also includes a control circuit for generating non-linear control signals that are responsive to process characteristics of the FETs, such that the degeneration resistance FET and load resistance FETs may be controlled more consistently and independently from process variations.Type: ApplicationFiled: September 17, 2007Publication date: March 19, 2009Applicant: Finisar CorporationInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Jonathan B. Ashbrook
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Publication number: 20090072903Abstract: A variable gain amplifier and offset cancellation loop circuit and methods for tracking and correcting DC offset errors that may vary in accordance with the gain of the variable gain amplifier. The circuit is designed to provide tracking of rapid changes in the offset error while maintaining a desired overall frequency response of the combined variable gain amplifier and offset loop. The offset loop cancellation circuit has a wide enough bandwidth to allow the offset cancellation loop to track rapid changes in offset errors that result from rapid changes to the amplifier's gain setting. A control circuit is provided to prevent the large offset cancellation loop bandwidth from having a detrimental effect on the amplifier's overall bandwidth when the amplifier is set to high levels of forward gain by adjusting the offset cancellation loop gain as the forward gain of the amplifier is altered.Type: ApplicationFiled: September 17, 2007Publication date: March 19, 2009Applicant: FINISAR CORPORATIONInventors: Hyeon Min Bae, Naresh Ramnath Shanbhag, Jonathan B. Ashbrook
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Patent number: 6671218Abstract: A system and method is disclosed for simultaneously searching and refreshing a memory array of a dynamic content addressable memory (DCAM). According to the disclosed invention, the information stored in a row of DCAM cells being refreshed is transferred from the memory array into sense amplifiers, during a read phase of a refresh operation. A search for a matching entry can then be performed, with respect to the information that is transferred to the sense amplifiers. To determine if there is a match, search information is simultaneously compared to the information that has been transferred to the sense amplifiers and to the information that is stored in other rows of DCAM cells of said memory array. Finally, the refresh of that row is completed by restoring the information from the sense amplifiers to that row of DCAM cells.Type: GrantFiled: December 11, 2001Date of Patent: December 30, 2003Assignee: International Business Machines CorporationInventors: Paul Gutwin, Jonathan B. Ashbrook, Michael Bogaczyk, Albert M. Chu, Ezra Hall, Daryl Seitzer
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Publication number: 20030112686Abstract: A system and method is disclosed for simultaneously searching and refreshing a memory array of a dynamic content addressable memory (DCAM). According to the disclosed invention, the information stored in a row of DCAM cells being refreshed is transferred from the memory array into sense amplifiers, during a read phase of a refresh operation. A search for a matching entry can then be performed, with respect to the information that is transferred to the sense amplifiers. To determine if there is a match, search information is simultaneously compared to the information that has been transferred to the sense amplifiers and to the information that is stored in other rows of DCAM cells of said memory array. Finally, the refresh of that row is completed by restoring the information from the sense amplifiers to that row of DCAM cells.Type: ApplicationFiled: December 11, 2001Publication date: June 19, 2003Applicant: International Business Machines CorporationInventors: Paul Gutwin, Jonathan B. Ashbrook, Michael Bogaczyk, Albert M. Chu, Ezra Hall, Daryl Seitzer
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Patent number: 6487101Abstract: A method and structure for a content addressable memory (CAM) array having a plurality of memory cells. Each of the memory cells has capacitive storage devices, transistors connected to the storage devices, a wordline connected to and controlling the transistors, bitlines connected to the storage devices through the transistors, combined search and global bitlines connected to the capacitive storage devices. These cells are further arranged into columns, each containing multiplexers connected to the combined search and global bitlines, data-in lines connected to the multiplexers, and search-data lines connected to the multiplexers. Further, the multiplexers select between the data-in lines and the search-data lines to allow the combined search and global bitlines to be alternatively used as data lines and search lines. Also, in the invention each of the columns further has drivers between the multiplexers and the combined search and global bitlines.Type: GrantFiled: October 2, 2001Date of Patent: November 26, 2002Assignee: International Business Machines CorporationInventors: Jonathan B. Ashbrook, Robert E. Busch, Albert M. Chu, Daryl M. Seitzer