Patents by Inventor Dave Walker

Dave Walker 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: 7680420
    Abstract: A method of synthesizing a modulated optical signal using a laser cascaded with an amplitude modulator. A phase drive signal VF(t) is derived for driving the laser to generate an optical carrier signal with a desired phase ?(t). An amplitude drive signal VS(t) is then derived for driving the amplitude modulator to impose a desired amplitude S(t) onto the optical carrier signal generated by the laser. The amplitude drive signal VS(t) is compensated for amplitude modulation of the optical carrier signal generated by the laser.
    Type: Grant
    Filed: June 21, 2004
    Date of Patent: March 16, 2010
    Assignee: Nortel Networks Limited
    Inventors: Dave Walker, Kim B. Roberts, Maurice O'Sullivan, Leo Strawczynski, James Whiteaway, Christopher Fludger, Han Henry Sun, Adrien Comeau
  • Patent number: 7092409
    Abstract: A timing network for a wireless communication network includes first and second Timing Unit Board (TUB) and processor boards for processing speech channels of the radio network, each processor board having a local timer that is slave to “PSTN time” from a Public Switch Telephone Network (PSTN). The first and second TUB each alternately transmits a timing cell containing time information to each processor board over a transport network. Each processor board realigns its local timer with the time information contained in a received timing cell whenever its local timer drifts from the time information contained in the received timing cell by a predetermined time offset. When one of the TUBs fails to transmit timing cells to the processor boards or transmits timing cells containing erroneous time information, the processor boards rely on the remaining TUB for timing cells to realign their local timers.
    Type: Grant
    Filed: March 21, 2001
    Date of Patent: August 15, 2006
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Dexter Chun, Steve Hicks, Bob Knight, KC Lee, Ravi Palakodety, Dave Walker, Jun Zhang
  • Patent number: 6898212
    Abstract: A Base Station Controller (BSC) that reduces the occurrence of audible noise in a Code Division Multiple Access (CDMA) radio network is provided. The BSC according to one embodiment of the present invention comprises a Media Stream Board (MSB) for compressing groups of 160 PCM speech samples from a Public Switch Telephone Network (PSTN) into vocoded frames, and a Special Purpose Board (SPB) for reformatting the vocoded frames from the MSB into over-the-air CDMA vocoded frames. The MSB and SPB each have a local timer that is slave to “PSTN time”. The BSC further comprises a Timing Unit Board (TUB) connected to a GPS receiver. The TUB receives “GPS time” from the GPS receiver. The TUB generates timing cells, each containing time-of-day information according to “GPS time”. The TUB distributes the timing cells to the MSB and the SPB over an Asynchronous Transfer Mode (ATM) network. The MSB and SPB use the received timing cells to compare their local timer, which tracks “PSTN time”, to “GPS time”.
    Type: Grant
    Filed: November 14, 2000
    Date of Patent: May 24, 2005
    Assignee: Telefonaktiebolaget LM Ericsson (publ)
    Inventors: Dexter Chun, Manoj Deshpande, Steve Hicks, Bob Knight, KC Lee, Ravi Palakodety, Ramesh Ramaswamy, Gustavo Serena, Dave Walker, Jun Zhang
  • Publication number: 20020136172
    Abstract: A timing network for a wireless communication network includes first and second Timing Unit Board (TUB) and processor boards for processing speech channels of the radio network, each processor board having a local timer that is slave to “PSTN time” from a Public Switch Telephone Network (PSTN). The first and second TUB each alternately transmits a timing cell containing time information to each processor board over a transport network. Each processor board realigns its local timer with the time information contained in a received timing cell whenever its local timer drifts from the time information contained in the received timing cell by a predetermined time offset. When one of the TUBs fails to transmit timing cells to the processor boards or transmits timing cells containing erroneous time information, the processor boards rely on the remaining TUB for timing cells to realign their local timers.
    Type: Application
    Filed: March 21, 2001
    Publication date: September 26, 2002
    Applicant: Telefonaktiebolaget LM Ericsson
    Inventors: Dexter Chun, Steve Hicks, Bob Knight, Kc Lee, Ravi Palakodety, Dave Walker, Jun Zhang