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Xiaofen Chen

from Palos Verdes Peninsula, CA
Age ~62
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Also known as:
Xiao Fen Chen, Xiao-Fen Chen, Chen Xiaofen, Chen Xiao-Fen, N Chen
Phone and address:
4200 Cartesian Cir, Palos Verdes Estates, CA 90274
(310) 613-8008
Related to:
Yong Chen, 59Jiaqi ChenRozita Chen, 59Kevin P Chen, 57Liquan Chen, 51
Connected to:
Abre G Chen, 65Adele Chen, 52Adeline K Chen, 39Ai M Chen, 60Ai C Chen, 79Aiping Chen, 63Alen Y Chen, 68Alma Chen, 29Amanda Chen, 44Amanda T Chen, 62

Xiaofen Chen Phones & Addresses

  • 4200 Cartesian Cir, Palos Verdes Peninsula, CA 90274 (310) 613-8008
  • Palos Verdes Estates, CA
  • 2615 Coeur D Alene Dr, West Linn, OR 97068
  • 11400 Rochester Ave, Los Angeles, CA 90025
  • Chelmsford, MA
  • Storrs Mansfield, CT
  • Beaverton, OR

Resumes

Resumes

Xiaofen Chen Photo 1

Xiaofen Chen

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Xiaofen Chen Photo 2

Postdoc At Ucla

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Position:
Postdoc at UCLA
Location:
Greater Los Angeles Area
Industry:
Research
Work:
UCLA since Sep 2009
Postdoc
Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences Sep 2006 - Jan 2007
Teaching Assistant
Education:
David Geffen School of Medicine at UCLA 2009 - 2012
Postdoc research, Biochemistry and Molecular Biology Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences 2004 - 2009
Doctor of Philosophy (Ph.D.), Biochemistry and Molecular Biology Xiamen University 2000 - 2004
Bachelor's degree, Biology, General
Languages:
Chinese
English

Publications

Us Patents

Method Of Estimating Pilot Signal Phase In A Digitally Modulated Rf Signal

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US Patent:
6366621, Apr 2, 2002
Filed:
Nov 3, 1998
Appl. No.:
09/185218
Inventors:
Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
H03D 124
US Classification:
375321, 329357
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.

Method Of Estimating Timing Phase And Rate Offsets In Digital Data

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US Patent:
6366629, Apr 2, 2002
Filed:
Nov 3, 1998
Appl. No.:
09/185421
Inventors:
Xiaofen Chen - West Linn OR
Thomas L. Kuntz - Portland OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
H04L 700
US Classification:
375355, 348 21
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. The iterative cross-correlation and resampling process continues until the rate of change of timing phase and rate offset values are minimized.

Reference Frequency Spur Cancellation In Synthesized Measurement Receivers

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US Patent:
6384589, May 7, 2002
Filed:
Apr 4, 2001
Appl. No.:
09/826495
Inventors:
Linley F. Gumm - Beaverton OR
Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
G01R 1320
US Classification:
324 7626
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 receivers 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.

Interference Cancellation In Antenna Test

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US Patent:
6542112, Apr 1, 2003
Filed:
Mar 6, 2002
Appl. No.:
10/093152
Inventors:
Xiaofen Chen - West Linn OR
Soraya J. Matos - Beaverton OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
G01S 740
US Classification:
342165
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. Then the interference frequency is measured, an interference phase shift between the two data acquisitions is calculated, an interference vector for the combined reflection/interference vector is predicted using the interference vector and the phase shift, and the predicted interference vector is subtracted from the signal vector to obtain the actual reflection signal for the antenna in the absence of interference.

Broadband Receiver Amplitude/Phase Normalization Using A Broadband Temperature Compensated Noise Source And A Pseudo Random Sequence Generator

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US Patent:
6636722, Oct 21, 2003
Filed:
Sep 12, 2000
Appl. No.:
09/660561
Inventors:
Donald J. Dalebroux - Vernonia OR
Xiaofen Chen - West Linn OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
H04B 1700
US Classification:
455 671, 455 674, 455423, 455425, 324601, 324603, 375224, 375229
Abstract:
A method of broadband receiver amplitude/phase normalization uses internal normalization sourcesâa 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.

Measurement Receiver Demodulator

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US Patent:
6671334, Dec 30, 2003
Filed:
Nov 3, 1998
Appl. No.:
09/185419
Inventors:
Thomas L. Kuntz - Portland OR
Xiaofen Chen - West Linn OR
Nikhil M. Deshpande - Beaverton OR
Kyle L. Bernard - Tigard OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
H04L 2706
US Classification:
375340, 375349
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.

Calibration For Vector Network Analyzer

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US Patent:
6701265, Mar 2, 2004
Filed:
Mar 5, 2002
Appl. No.:
10/093171
Inventors:
Thomas C. Hill - Beaverton OR
Xiaofen Chen - West Linn OR
Soraya J. Matos - Beaverton OR
Leroy J. Willmann - Portland OR
Kyle L. Bernard - Tigard OR
Linley F. Gumm - Beaverton OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
G01D 1800
US Classification:
702 91
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.

Enhanced Constellation Display For Vsb Television Signals

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US Patent:
6741642, May 25, 2004
Filed:
Apr 3, 1998
Appl. No.:
09/055049
Inventors:
Kyle L. Bernard - Tigard OR
Xiaofen Chen - West Linn OR
Thomas L. Kuntz - Portland OR
Assignee:
Tektronix, Inc. - Beaverton OR
International Classification:
G06F 1100
US Classification:
375228
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.
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Xiaofen Chen from Palos Verdes Peninsula, CA, age ~62 Get Report