Patents by Inventor Xiaofen Chen

Xiaofen Chen 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).

  • Publication number: 20240139348
    Abstract: Disclosed are a multi-modality molecular imaging probe, and a preparation method and use thereof. The multi-modality molecular imaging probe has an ABA structure, with a magnetic functional unit of a gadolinium complex at the center, and two identical phosphorescent functional units of an iridium complex, which are reasonably integrated into the same one complex molecule. The multi-modality molecular imaging probe simultaneously introduces two optical functional units of the iridium complex and one magnetic functional unit of a gadolinium chelate in the same one complex molecule, which exhibits magnetic-optical dual functional properties. It therefore could be used to prepare both a contrast agent for magnetic resonance imaging and an optical probe for optical imaging.
    Type: Application
    Filed: September 12, 2023
    Publication date: May 2, 2024
    Inventors: Jiaxi Ru, Xiaoliang Tang, Xiufeng Huang, Weisheng Liu, Chao Liang, Lingling Kang, Xiaofen Chen, Xian Shen
  • Publication number: 20240105370
    Abstract: The present invention discloses a high-entropy soft magnetic alloy with 900 K high-temperature resistance, comprising Fe, Co, Ni, Si and Al, and the atomic percent of the alloy composition is expressed as FexCoyNizSimAln, wherein x=40%-80%, y=20%-60%, z=0-30%, m=0-20%, n=0-20%, and x+y+z+m+n=100%; the atomic percent of other doping elements is p=0-5%, and 0.5?m/n?3; the performance indexes of the material include: at room temperature, saturation magnetization Ms=90-150 emu/g, and coercive force Hc=0.1-15 Oe; and at 900 K, saturation magnetization Ms=70-130 emu/g, and coercive force Hc=0.1-25 Oe.
    Type: Application
    Filed: December 6, 2023
    Publication date: March 28, 2024
    Inventors: Haizhou Wang, Runqiu Lang, Haiyang Chen, Yandong Wang, Lei Zhao, Changwang Zhu, Xiaofen Zhang, Lixia Yang, Dongling Li, Xuejing Shen, Yunhai Jia
  • Publication number: 20230268324
    Abstract: Provided are a display panel and a display device. The display panel includes a substrate and multiple display units located on a side of the substrate. The display units include multiple light-emitting elements. The light-emitting elements include main light-emitting elements and backup light-emitting elements. The number of main light-emitting elements is greater than the number of backup light-emitting elements. The main light-emitting elements are arranged in a first direction. In a second direction, a backup light-emitting element is located between two main light-emitting elements. In the second direction, at least two main light-emitting elements are disposed adjacent to each other. When the display panel is driven to display an image, and when a dead pixel appears in a main light-emitting element, a backup light-emitting element emits light to replace the main light-emitting element in which the dead pixel appears for display.
    Type: Application
    Filed: April 28, 2023
    Publication date: August 24, 2023
    Applicant: Xiamen Tianma Microelectronics Co., Ltd.
    Inventors: Liting FANG, Xiaofen CHEN, Wei WANG
  • Patent number: 9176213
    Abstract: A method and system for providing adaptive coded modulation in LEO satellite communication system is provided. The received power signal at the receiver is predicted by the LEO satellite transmitter without using channel feedback from the receiver. The receiver rapidly detects changes in transmission rate and changes its demodulation rate in tandem with the LEO satellite. Certain conditions that vary slowly, such as local weather and ground moisture level, are provided to the transmitter from the receiver at a much slower rate than that used in normal data communications.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: November 3, 2015
    Assignee: Northrop Grumman Systems Corporation
    Inventors: Daniel N. Liu, Michael P. Fitz, Xiaofen Chen
  • Patent number: 7373282
    Abstract: A fault severity check and source identification method for a frequency domain instrument accesses acquired reflection data for a transmission line under test. From the acquired data reflection surfaces are isolated as a function of distance. Each reflection surface is examined to produce a frequency response profile and a worst-case reflection response to determine fault severity. The frequency response profile may also be correlated in a pattern recognition algorithm with known reference source profiles to determine the source identification for the fault.
    Type: Grant
    Filed: July 31, 2002
    Date of Patent: May 13, 2008
    Assignee: Tektronix, Inc.
    Inventor: Xiaofen Chen
  • Patent number: 7184406
    Abstract: A display of code domain power (CDP) for a code domain multiple access (CDMA) signal having multiple spreading factors is in the form of a three-dimensional graphic having as axes code domain power, code index and spreading factor to provide a visual indication of both power and spreading factor for active codes. Sub-codes of base codes may be identified by any suitable means, such as highlighting. Sub-codes may be suppressed and the power level of the base codes adjusted accordingly to represent the total power of the active codes.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: February 27, 2007
    Assignee: Tektronix, Inc.
    Inventors: Kathryn A. Engholm, Xiaofen Chen
  • Publication number: 20060190201
    Abstract: A method of deriving a composite step function response from a band-limited transmission channel frequency response includes the steps of obtaining a time domain response from the band limited frequency response, identifying reflection events from the time domain response, estimating an impulse response from the identified reflection events, and determining the composite step function from the estimated impulse response. The impulse response estimation is obtained from the observed time domain response as y(n)=h(n)?h(n){circumflex over (×)}w(n) where y(n) is the observed time domain response, h(n) is the impulse response to be estimated and w(n) is a window function w(n)=sin(?0*n/Fs)?n where ?0 is the initial frequency and Fs is the sample rate frequency. For reduction in calculation expense an impulse response segment is calculated over a narrow range of data about each reflection event.
    Type: Application
    Filed: April 7, 2006
    Publication date: August 24, 2006
    Inventor: Xiaofen Chen
  • Patent number: 6741642
    Abstract: A modulation analyzer includes a smoothing processor which processes the coordinates of symbol landing points to generate a curve that optimally fits the landing points under a selected criterion.
    Type: Grant
    Filed: April 3, 1998
    Date of Patent: May 25, 2004
    Assignee: Tektronix, Inc.
    Inventors: Kyle L. Bernard, Xiaofen Chen, Thomas L. Kuntz
  • Patent number: 6701265
    Abstract: An improved calibration method for a vector network analyzer stores sparse calibration data, interpolates system error data from the sparse calibration data for each measurement by the vector network analyzer, and creates calibrated measurement data from the system error data and uncorrected measurement data at each measurement frequency. The sparse calibration data may be generated by measuring every Nth frequency step over a calibration frequency range greater than a specified measurement frequency range, or by measuring every frequency step over the calibration frequency range and compressing the resulting measurement data. The interpolation may be achieved by using a curve-fit algorithm, such as a parametric polynomial curve fitting algorithm.
    Type: Grant
    Filed: March 5, 2002
    Date of Patent: March 2, 2004
    Assignee: Tektronix, Inc.
    Inventors: Thomas C. Hill, Xiaofen Chen, Soraya J. Matos, Leroy J. Willmann, Kyle L. Bernard, Linley F. Gumm
  • Publication number: 20040022195
    Abstract: A fault severity check and source identification method for a frequency domain instrument accesses acquired reflection data for a transmission line under test. From the acquired data reflection surfaces are isolated as a function of distance. Each reflection surface is examined to produce a frequency response profile and a worst-case reflection response to determine fault severity. The frequency response profile may also be correlated in a pattern recognition algorithm with known reference source profiles to determine the source identification for the fault.
    Type: Application
    Filed: July 31, 2002
    Publication date: February 5, 2004
    Inventor: Xiaofen Chen
  • Patent number: 6671334
    Abstract: A measurement receiver demodulator has a first processing channel for producing a filtered signal sample output where the signal samples are processed through a transmission system receiver filter and a second processing channel producing an unfiltered signal sample output where the signal samples are not processed through the transmission system receiver filter. The first processing channel down converts digitally modulated IF signal samples and filters the down converted signal samples using a combined transmission system receiver filter and front end hardware compensation filter. A synchronizer produces timing phase and rate offset parameters that are applied to a resampling filter to synchronize the filtered signal samples to symbol instances of the symbol modulation. The filtered, time-aligned signal samples are scaled using a derived scaling factor. A pilot offset level, if present, is estimated and removed.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: December 30, 2003
    Assignee: Tektronix, Inc.
    Inventors: Thomas L. Kuntz, Xiaofen Chen, Nikhil M. Deshpande, Kyle L. Bernard
  • Patent number: 6636722
    Abstract: A method of broadband receiver amplitude/phase normalization uses internal normalization sources—a thermally compensated noise source and a pseudo random sequence generator. A calibrated signal is applied to the input of the broadband receiver and processed by a digital signal processor to generate a gain versus frequency table. Then the internal noise source is applied to the input of the broadband receiver and process by a digital signal processor to generate a noise level versus frequency table. Finally the internal pseudo random sequence generator applies a pseudo random sequence waveform to the input of the broadband receiver, the pseudo random sequence waveform being process by the digital signal processor to generate equalization filter coefficients for the IF stages.
    Type: Grant
    Filed: September 12, 2000
    Date of Patent: October 21, 2003
    Assignee: Tektronix, Inc.
    Inventors: Donald J. Dalebroux, Xiaofen Chen
  • Publication number: 20030171886
    Abstract: An improved calibration method for a vector network analyzer stores sparse calibration data, interpolates system error data from the sparse calibration data for each measurement by the vector network analyzer, and creates calibrated measurement data from the system error data and uncorrected measurement data at each measurement frequency. The sparse calibration data may be generated by measuring every Nth frequency step over a calibration frequency range greater than a specified measurement frequency range, or by measuring every frequency step over the calibration frequency range and compressing the resulting measurement data. The interpolation may be achieved by using a curve-fit algorithm, such as a parametric polynomial curve fitting algorithm.
    Type: Application
    Filed: March 5, 2002
    Publication date: September 11, 2003
    Inventors: Thomas C. Hill, Xiaofen Chen, Soraya J. Matos, Leroy J. Willmann, Kyle L. Bernard, Linley F. Gumm
  • Publication number: 20030063586
    Abstract: A display of code domain power (CDP) for a code domain multiple access (CDMA) signal having multiple spreading factors is in the form of a three-dimensional graphic having as axes code domain power, code index and spreading factor to provide a visual indication of both power and spreading factor for active codes. Sub-codes of base codes may be identified by any suitable means, such as highlighting. Sub-codes may be suppressed and the power level of the base codes adjusted accordingly to represent the total power of the active codes.
    Type: Application
    Filed: September 28, 2001
    Publication date: April 3, 2003
    Inventors: Kathryn A. Engholm, Xiaofen Chen
  • Patent number: 6542112
    Abstract: A method of interference cancellation in antenna test measurements is achieved by acquiring an acquisition at a test port of an antenna test instrument in response to an internal signal source, stamping the data acquisition time, and measuring a signal vector that has both a reflection signal component and an interference signal component. Another acquisition at the test port without the internal signal source is obtained with limited data points to detect whether there are interference signals. If there is significant interference power, a complete acquisition is obtained without the internal signal source, the data acquisition time is stamped, and an interference vector that has only the interference signal is measured.
    Type: Grant
    Filed: March 6, 2002
    Date of Patent: April 1, 2003
    Assignee: Tektronix, Inc.
    Inventors: Xiaofen Chen, Soraya J. Matos
  • Publication number: 20030035376
    Abstract: A method of deriving a composite step function response from a band-limited transmission channel frequency response includes the steps of obtaining a time domain response from the band limited frequency response, identifying reflection events from the time domain response, estimating an impulse response from the identified reflection events, and determining the composite step function from the estimated impulse response.
    Type: Application
    Filed: August 20, 2001
    Publication date: February 20, 2003
    Inventor: Xiaofen Chen
  • Patent number: 6384589
    Abstract: Reference frequency spur cancellation in a synthesized measurement receiver is achieved by determining for any given frequency to which the receiver is tuned a list of integer multipliers of the reference frequency that produce spurious signals in the receiver's passband. For those values the amplitude and phase for each spurious signal is determined in the digital domain and subtracted from the digital signal from the receiver. The reference frequency is then offset slightly and the measurement repeated. The maximum values between each measurement are combined to produce a measurement for the input signal without spurious signals.
    Type: Grant
    Filed: April 4, 2001
    Date of Patent: May 7, 2002
    Assignee: Tektronix, Inc.
    Inventors: Linley F. Gumm, Thomas L. Kuntz, Xiaofen Chen
  • Patent number: 6366621
    Abstract: A method of estimating pilot signal phase embedded in a wideband digital signal modulating a RF signal that is down converted to an intermediate frequency and digitized includes the steps of summing a block of the signal samples for removing the modulation data and generating data values representative of vector locations of the pilot signal with each data value representing an angular rotation of the pilot signal vector, and calculating the phase of the pilot signal by determining the arc tangent of the data values. The method produces a computationally efficient narrow band filter generated at the pilot signal frequency by simple addition of the digital data values. The method is usable in a software based 8-VSB digital television demodulation system.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: April 2, 2002
    Assignee: Tektronix, Inc.
    Inventors: Thomas L. Kuntz, Xiaofen Chen
  • Patent number: 6366629
    Abstract: A method of estimating symbol timing phase and rate offsets of a sampled digitally modulated signal having repetitive symbol sync sequences includes the steps of estimating symbol sync sequence locations in a block of signal samples using a cross-correlation with a reference pattern of ideal symbol sync sequences. Signal samples within subranges defining the symbol sync sequences in the block of signal samples are filtered for removing intersymbol interference. An iterative process of cross-correlation of the filtered signal samples within the subranges using the reference pattern of ideal symbol sync sequences and an ideal symbol sync correction pattern generates timing phase and rate offset values that are used to derive filter coefficients for resampling the filtered signal samples within the subranges using an interpolating filter. The rate offset value is derived using a linear model and performing an optimal estimation.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: April 2, 2002
    Assignee: Tektronix, Inc.
    Inventors: Xiaofen Chen, Thomas L. Kuntz
  • Patent number: 6275523
    Abstract: A system for in-service nonlinearity measurements measures such nonlinearities by way of comparing received linear error-corrected unfiltered signal samples with re-generated reference signal samples to calculate magnitude and phase nonlinear error values. Linear distortion is removed from the received signal samples in order to truly characterize nonlinear behavior of the transmitter. The linear error-corrected received signal samples are generated without applying the receiver shaping filtering. Reference signal samples are re-generated from estimated transmitted symbols from the unfiltered linear error-corrected received signal samples. The transmitted symbols are estimated using a multi-region slicer which dynamically estimates constellation decision levels from the unfiltered signal samples.
    Type: Grant
    Filed: November 3, 1998
    Date of Patent: August 14, 2001
    Assignee: Textronic, Inc.
    Inventors: Xiaofen Chen, Linley F. Gumm, Thomas L. Kuntz