Patents by Inventor Stefan Langenbach

Stefan Langenbach 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: 8068572
    Abstract: This invention discloses a self-timing method for phase adjustment. An analog signal is digitized at a first and second phase with respect to the symbols comprised in an analog signal in order to obtain first and second quantized samples. Then a first counter out of a first plurality of counters is increased if said first quantized sample has a first digital value to which said first counter is associated. Moreover a second counter out of a second plurality of counters is increased if a second quantized sample has a second digital value to which the second counter is associated. Finally the sampling phase is adjusted based on the values of the counters of the first and second plurality of counters. Moreover a digitizing, self-timing circuit is disclosed.
    Type: Grant
    Filed: February 25, 2004
    Date of Patent: November 29, 2011
    Assignee: Cisco Technology, Inc.
    Inventors: Stefan Langenbach, Negojsa Stojanovic
  • Patent number: 7738602
    Abstract: The invention relates to a method for channel estimation. The method comprises digitizing an analog signal representing a sequence of symbols thereby associating one digital word out to the level of said analog signal at each sampling time. The most likely sequence of said symbols is detected. To this end branch metrics are provided. According to one embodiment, a symbol period comprises at least two sampling times. Moreover, the branch metrics are obtained from frequencies of digital words resulting from a digitizing and the symbols of the most likely sequence. According to another embodiment, a symbol period comprises at least one sampling time. Events are counted wherein each event is defined by a channel state and a current digital word. Each channel state is defined by a pattern of symbols relative to a current symbol determined at the time of a current digital word. A model distribution is fitted to event counts and a branch metrics is obtained from the fitted model distribution.
    Type: Grant
    Filed: July 1, 2004
    Date of Patent: June 15, 2010
    Assignee: CoreOptics, Inc.
    Inventors: Stefan Langenbach, Nebojsa Stojanovic
  • Patent number: 7319363
    Abstract: This invention relates to a method for controlling an amplification within a receiver. The gain of a variable gain amplifier which amplifies an input signal to obtain a gain-controlled signal is set. Said gain controlled signal is analog-to-digital converted. Thereby digital words are generated. Each digital word has a value out of a plurality of possible digital values. Digital words having a value within a first and a second subset of the possible digital values are counted in order to generate a first and a second counter value. The gain is set in accordance with the first and second counter values in a fashion that all counter values are as equal as possible. Furthermore, this invention is related to a circuit to be used within a receiver for adjusting the gain of a variable gain amplifier in order to ensure a proper analog-to-digital conversion.
    Type: Grant
    Filed: April 23, 2004
    Date of Patent: January 15, 2008
    Assignee: CoreOptics, Inc.
    Inventors: Stefan Langenbach, Nebojsa Stojanovic
  • Publication number: 20070291886
    Abstract: This invention discloses a self-timing method for phase adjustment. An analog signal is digitized at a first and second phase with respect to the symbols comprised in an analog signal in order to obtain first and second quantized samples. Then a first counter out of a first plurality of counters is increased if said first quantized sample has a first digital value to which said first counter is associated. Moreover a second counter out of a second plurality of counters is increased if a second quantized sample has a second digital value to which the second counter is associated. Finally the sampling phase is adjusted based on the values of the counters of the first and second plurality of counters. Moreover a digitizing, self-timing circuit is disclosed.
    Type: Application
    Filed: February 25, 2004
    Publication date: December 20, 2007
    Inventors: Stefan Langenbach, Negojsa Stojanovic
  • Publication number: 20070109053
    Abstract: This invention relates to a method for controlling an amplification within a receiver. The gain of a variable gain amplifier which amplifies an input signal to obtain a gain-controlled signal is set. Said gain controlled signal is analog-to-digital converted. Thereby digital words are generated. Each digital word has a value out of a plurality of possible digital values. Digital words having a value within a first and a second subset of the possible digital values are counted in order to generate a first and a second counter value. The gain is set in accordance with the first and second counter values in a fashion that all counter values are as equal as possible. Furthermore, this invention is related to a circuit to be used within a receiver for adjusting the gain of a variable gain amplifier in order to ensure a proper analog-to-digital conversion.
    Type: Application
    Filed: April 23, 2004
    Publication date: May 17, 2007
    Applicant: CoreOptics Inc.
    Inventors: Stefan Langenbach, Nebojsa Stojanovic
  • Publication number: 20060274861
    Abstract: The invention relates to a method for channel estimation. The method comprises digitizing an analog signal representing a sequence of symbols thereby associating one digital word out to the level of said analog signal at each sampling time. The most likely sequence of said symbols is detected. To this end branch metrics are provided. According to one embodiment, a symbol period comprises at least two sampling times. Moreover, the branch metrics are obtained from frequencies of digital words resulting from a digitizing and the symbols of the most likely sequence. According to another embodiment, a symbol period comprises at least one sampling time. Events are counted wherein each event is defined by a channel state and a current digital word. Each channel state is defined by a pattern of symbols relative to a current symbol determined at the time of a current digital word. A model distribution is fitted to event counts and a branch metrics is obtained from the fitted model distribution.
    Type: Application
    Filed: July 1, 2004
    Publication date: December 7, 2006
    Inventors: Stefan Langenbach, Nebojsa Stojanovic