Patents by Inventor Weizhong Chen

Weizhong 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).

  • Patent number: 6961391
    Abstract: A signal processor and method therein that is arranged and constructed to recover a sequence of symbols from a received signal is discussed. The processor includes a symbol selector for selecting a symbol based on the received signal over a time period including previous symbol periods, said symbol period, and a number of additional symbol periods, where said number of additional symbol periods depends on the inter symbol interference associated with the received signal. The processor utilizes an MLSE approach that is adapted to be especially calculation efficient.
    Type: Grant
    Filed: March 30, 2001
    Date of Patent: November 1, 2005
    Assignee: Motorola, Inc.
    Inventor: Weizhong Chen
  • Patent number: 6958671
    Abstract: The present invention provides an electrical contactor for connecting and disconnecting an electrical power source to an electrical device wherein the electrical power source is electrically connected to a line terminal having a line terminal electrical contact and the electrical device is electrically connected to a load terminal electrical contact. The electrical contactor contains a plurality of electrical contacts which contact the line and load terminal electrical contacts.
    Type: Grant
    Filed: November 15, 2001
    Date of Patent: October 25, 2005
    Assignee: Square D Company
    Inventors: William Weizhong Chen, R. Kent Crawford
  • Publication number: 20050111530
    Abstract: A timing and carrier error detector module (127) of a communication receiver (111). The timing and carrier error detector module uses phase information of a correlated signal (e.g. a Barker de-spread signal) to generate a timing signal and carrier error signal. In one example, the phase information includes a phase error signal of the correlated signal. In one example, the timing and carrier error detector module calculates an indication of the variance of the phase error signal for a plurality of sample positions over a plurality of Barker symbol intervals. The timing signal is based upon the sample position having a minimum indication of a variance.
    Type: Application
    Filed: November 25, 2003
    Publication date: May 26, 2005
    Inventors: Weizhong Chen, Sekchin Chang, Satish Kulkarni
  • Publication number: 20050079850
    Abstract: A method for removing direct current (DC) interference from a signal received by a communication receiver is provided that removes both a DC offset signal induced by the communication receiver and transmitter. The method includes removing the estimated DC offset from the received signal, correcting a frequency shift in the received signal, estimating a second DC offset signal induced by a source of the received signal, such as a transmitter and removing the estimated second DC offset from the received signal. The receiver DC offset signal is estimated and removed prior to performing a timing carrier offset correction using Barker code manipulation to remove receiver-induced DC offset interference and to sum all Barker chips after effectively multiplying Barker codes to correlate to a Barker sequence unaffected by the receiver DC offset signal.
    Type: Application
    Filed: October 12, 2004
    Publication date: April 14, 2005
    Inventors: Weizhong Chen, Robert Molina
  • Patent number: 6836520
    Abstract: A synchronization signal includes a plurality of predetermined synchronization symbols shaped by a predetermined symbol pulse. A receiver (100) receives (202) a signal including the synchronization signal, and a processor (106)determines (204) a first plurality of cross-correlations between the predetermined symbol pulse and the received signal. The processor calculates (206) a plurality of sums of products of the plurality of predetermined synchronization symbols and a predetermined subset of the first plurality of cross-correlations. The plurality of sums are mathematically equivalent to a second plurality of cross-correlations between the synchronization signal and the received signal. The processor locates (208) a peak of the plurality of sums to establish receiver synchronization.
    Type: Grant
    Filed: November 10, 2000
    Date of Patent: December 28, 2004
    Assignee: Motorola, Inc.
    Inventors: Weizhong Chen, Leo Dehner
  • Publication number: 20040184564
    Abstract: The present invention discloses an improved method of timing synchronization with transmitted data packets in a receiver on a communication channel using differential phase shift keying (DPSK) modulation—especially an RF wireless communication channel. The invention reduces the complexity of the circuits, especially the multipliers, required for digital signal processing. The invention also increases performance compared to previously known methods.
    Type: Application
    Filed: March 19, 2003
    Publication date: September 23, 2004
    Inventors: Weizhong Chen, Leo Dehner
  • Publication number: 20040017864
    Abstract: A system and method in a communication device (10) uses timing tracking to correct timing drifting due to the difference in frequency of a transmitter clock and a receiver clock. With the timing tracking, correlation values of three consecutive samples are calculated using the receive signal and the recovered symbols and then summed. A timing signal, (nk, frack) is updated based upon a metric calculated from a previous correlation value, R−1, present correlation value (R0) and a next con-elation value (R+1). Adjustment of timing signal is based on the relative location with respect to the current timing of a peak of a second order polynomial curve formed by the first correlation value R−1, the second correlation value Ro and the third correlation value R+1.
    Type: Application
    Filed: July 29, 2002
    Publication date: January 29, 2004
    Inventor: Weizhong Chen
  • Patent number: 6594328
    Abstract: A receiver (200) receives (402) a first signal including a sync portion (308) having a carrier acquisition segment (302) and a timing synchronization pattern (304), and a processing system (216) of the receiver calculates (404) a first plurality of squared magnitude Fourier transforms at a first plurality of frequencies on the carrier acquisition segment. The processing system derives (406) an initial carrier frequency error estimate by locating a peak in the first plurality of squared magnitude Fourier transforms, and corrects (408) the sync portion according to the initial carrier frequency error estimate, thereby producing a carrier-corrected sync portion. The processing system then removes (410) the timing synchronization pattern from the carrier-corrected sync portion, thereby producing a second signal having a residual carrier error.
    Type: Grant
    Filed: July 28, 1999
    Date of Patent: July 15, 2003
    Assignee: Motorola, Inc.
    Inventors: Weizhong Chen, Leo George Dehner
  • Publication number: 20030090351
    Abstract: The present invention provides an electrical contactor for connecting and disconnecting an electrical power source to an electrical device wherein the electrical power source is electrically connected to a line terminal having a line terminal electrical contact and the electrical device is electrically connected to a load terminal electrical contact. The electrical contactor contains a plurality of electrical contacts which contact the line and load terminal electrical contacts.
    Type: Application
    Filed: November 15, 2001
    Publication date: May 15, 2003
    Inventors: William Weizhong Chen, R. Kent Crawford
  • Patent number: 6511280
    Abstract: An adaptive Reed-Solomon(RS) decoder (207) and analogous methods arranged and constructed to decode a RS(n,k) encoded symbol stream, including; a code register (211), coupled to the symbol stream, for storing a received code word including code symbols, an index register (213) for storing a location information corresponding to each of a portion of the code symbols, a processor (215), coupled to the code register (211) and the index register (213), for performing soft decision decoding using an error parameter (217) and an erasure parameter (219) to provide corrected data (215) when the decoding is successful and to provide a failure indication (221) when decoding is unsuccessful, and a controller (223), coupled to the processor (215), for providing the error parameter and the erasure parameter and for adjusting the error parameter and the erasure parameter when the processor provides the failure indication.
    Type: Grant
    Filed: May 21, 1996
    Date of Patent: January 28, 2003
    Assignee: Motorola, Inc.
    Inventors: Pablo Eduardo Sammartino, Weizhong Chen
  • Patent number: 6487240
    Abstract: A receiver architecture includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter BT of about one-half the BT of the transmitter filter. A discriminator (208) is coupled to the selectivity filter for converting received symbols from the frequency domain to the time domain symbols. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a two-state maximum likelihood sequence estimation (MLSE) technique in which templates are optimized with a BT substantially less than the BT of the transmitter filter.
    Type: Grant
    Filed: November 10, 2000
    Date of Patent: November 26, 2002
    Assignee: Motorola, Inc.
    Inventor: Weizhong Chen
  • Patent number: 6473732
    Abstract: A signal analyzer (303) and method thereof using short-time signal analysis, preferably recursive, to obtain a time variant feature from a signal, the signal analyzer including a signal sampler (401) with an input register (403) for storing a sequence of samples of the signal, a multiplier (405) for weighting in accordance with, alternatively, a half-sine, cosine, 2nd order complex pole, or 3rd order complex pole function the sequence of samples to provide weighted samples of the signal, and a combiner (407) for combining the weighted samples to provide a signal feature estimate, such as a signal average or frequency dependent energy estimate, for the signal.
    Type: Grant
    Filed: October 18, 1995
    Date of Patent: October 29, 2002
    Assignee: Motorola, Inc.
    Inventor: Weizhong Chen
  • Publication number: 20020141506
    Abstract: A signal processor and method therein that is arranged and constructed to recover a sequence of symbols from a received signal is discussed. The processor includes a symbol selector for selecting a symbol based on the received signal over a time period including previous symbol periods, said symbol period, and a number of additional symbol periods, where said number of additional symbol periods depends on the inter symbol interference associated with the received signal. The processor utilizes an MLSE approach that is adapted to be especially calculation efficient.
    Type: Application
    Filed: March 30, 2001
    Publication date: October 3, 2002
    Applicant: MOTOROLA, INC.
    Inventor: Weizhong Chen
  • Patent number: 6437960
    Abstract: The present invention provides a current limiting circuit breaker having a plurality of current responsive devices for opening a pair of contacts upon short circuit conditions. One such device is a conventional magnetic tripping mechanism. The other device utilizes an insulating object driven by a magnetic force caused by the short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. In an alternative embodiment, at least one steel component is added to increase the magnetic force, thereby providing a greater force on the insulating object. An insulation component is also added to further suppress any arc generated between the contacts when going from a closed state to an open state.
    Type: Grant
    Filed: May 31, 2000
    Date of Patent: August 20, 2002
    Assignee: Square D Company
    Inventors: William Weizhong Chen, Brett Eugene Larson, Bruce F. Lindholm, Ron E. Stecker
  • Patent number: 6424673
    Abstract: A processor (306) is assigned a predetermined synchronization signal for use in communicating in a wireless communication system (100) The processor calculates (402) a total energy of the predetermined synchronization signal. A receiver front end (302) coupled to the processor receives (404) a signal which may include the predetermined synchronization signal, and calculates (406) a plurality of cross-correlation values between the received signal and the predetermined synchronization signal to locate a correlation peak. The processor also calculates (408) a plurality of detection metrics as a function of the plurality of cross-correlation values, the received signal, and the predetermined synchronization signal.
    Type: Grant
    Filed: November 10, 2000
    Date of Patent: July 23, 2002
    Assignee: Motorola, Inc.
    Inventors: Weizhong Chen, Leo Dehner
  • Publication number: 20020092829
    Abstract: The present invention provides a current limiting circuit breaker having a current responsive device for opening a pair of contacts or switch upon short circuit conditions. The current responsive device utilizes an insulating object driven by a magnetic force caused by a short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. The PTC elements could be pure metallic materials such as pure tungsten, pure iron, etc. Conductive polymer and ceramic PTC materials could also be used for some specific applications. The present invention also provides a method of electrically connecting a drive plate and a line terminal on the current limiting circuit breaker.
    Type: Application
    Filed: December 20, 2000
    Publication date: July 18, 2002
    Inventors: William Weizhong Chen, Frank Ehrenberger, Aaron Bottorff, Matt Sortland
  • Patent number: 6414256
    Abstract: The present invention provides a current limiting circuit breaker having a current responsive device for opening a pair of contacts or switch upon short circuit conditions. The current responsive device utilizes an insulating object driven by a magnetic force caused by a short circuit current. Upon opening of the contacts with the use of the insulating object, let-through current flows through a secondary contact, positioned on the insulating object, to a positive temperature coefficient resistivity element which limits the current and arcing in the contacts. The PTC elements could be pure metallic materials such as pure tungsten, pure iron, etc. Conductive polymer and ceramic PTC materials could also be used for some specific applications. The present invention also provides a method of electrically connecting a drive plate and a line terminal on the current limiting circuit breaker.
    Type: Grant
    Filed: December 20, 2000
    Date of Patent: July 2, 2002
    Assignee: Square D Company
    Inventors: William Weizhong Chen, Frank Ehrenberger, Aaron Bottorff, Matt Sortland
  • Publication number: 20020057746
    Abstract: A receiver architecture for receiving an FSK signal having a predetermined number of modulation levels includes a selectivity filter (206) for selectively passing a wanted channel and rejecting unwanted channels. The selectivity filter has a filter bandwidth of about one-half the bandwidth of a pre-modulation filter in a transmitter sending the FSK signal. A discriminator (208) is coupled to the selectivity filter for demodulating the signal. A symbol recovery processor (210) is coupled to the discriminator for recovering the symbols through a maximum likelihood sequence estimation (MLSE) technique utilizing N states for each symbol time, wherein N equals the predetermined number of modulation levels, and wherein templates used in the MLSE for symbol transitions are optimized with a bandwidth substantially less than the bandwidth of the pre-modulation filter.
    Type: Application
    Filed: February 27, 2001
    Publication date: May 16, 2002
    Applicant: MOTOROLA INC.
    Inventor: Weizhong Chen
  • Patent number: 6347127
    Abstract: A processing system (216) selects (1004) a portion (702-706) of a received signal including an evaluation symbol (702), along with a preceding symbol (704) received immediately before the evaluation symbol, and a following symbol (706) received immediately after the evaluation symbol; and prefixes (1006) to the portion of the received signal a previously estimated symbol (708) received immediately before the portion, thereby producing an evaluation portion (712, 904). The processing system then compares (1008) the evaluation portion with templates equal in length to the evaluation portion and including different combinations of trial symbols and the at least one previously estimated symbol, prefixed to the trial symbols; and estimates (1010) the evaluation symbol to be equal to a trial symbol in one of the templates having a highest correlation with the evaluation portion, the trial symbol having a position matching that of the evaluation symbol in the evaluation portion.
    Type: Grant
    Filed: May 10, 1999
    Date of Patent: February 12, 2002
    Assignee: Motorola, Inc.
    Inventor: Weizhong Chen
  • Patent number: 6289060
    Abstract: A receiver front end (604) receives sequence of symbols. A processor (606) coupled to the receiver front end computes a metric corresponding to the sequence of symbols. The metric is selected from one of: (a) a recursive metric having a structure m({overscore (a)}k)=m({overscore (a)}k−1)+{circumflex over (m)}(ak−N, . . . , ak−1, ak), wherein m({overscore (a)}k−1) and m({overscore (a)}k) are the cumulative metrics for symbols up to ak−1 and ak, respectively, and {circumflex over (m)}(ak−N, . . . , ak−1, ak) is the incremental metric, a function of (N+1) symbols {ak−N, . . . , ak−1, ak}, and (b) a non-recursive metric m({overscore (a)}k) that is an arbitrary function of a set of L submetrics {z1({overscore (a)}k), z2({overscore (a)}k), . . . , zL({overscore (a)}k)} m({overscore (a)}k)=m[z1({overscore (a)}k), z2({overscore (a)}k), . . .
    Type: Grant
    Filed: May 12, 2000
    Date of Patent: September 11, 2001
    Assignee: Motorola, Inc.
    Inventor: Weizhong Chen