Patents by Inventor Alan D. Muehlfeld

Alan D. Muehlfeld 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).

  • Apparatus and method for generating a data signal
    Patent number: 5554988
    Abstract: An apparatus is provided for generating a multiple-level amplitude modulated data signal. The circuit provides accurate data signal level control while minimizing transient errors. A controlling level, relative to an analog reference level is provided. Multiple bit reference levels are generated from the controlling level and analog reference level. A method is provided for selecting one of the reference levels.
    Type: Grant
    Filed: August 23, 1994
    Date of Patent: September 10, 1996
    Assignee: Motorola, Inc.
    Inventors: Michael H. Retzer, Alan D. Muehlfeld
  • Synchronization method in a frequency hopping local area network having dedicated control channels
    Patent number: 5509027
    Abstract: A method for a synchronizing user devices (12) performing handoffs includes providing a set of location synchronizing frequencies and data frequencies selected from a hopping set used by network access points (14). Each AP transmits synchronizing data (36) at the synchronizing frequencies during a portion of a short dwell (32), the short dwells (32) being interleaved between long dwells (30). When a user device (12) attempt a handoff, it tunes to at least one of the synchronizing frequencies and receives synchronizing information (36). The user device (12) then selects one AP (14) for link transfer and synchronizes its operation to the hopping set used by the selected AP (14).
    Type: Grant
    Filed: December 5, 1994
    Date of Patent: April 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Frederick W. Vook, William K. Doss, Alan D. Muehlfeld, Mai T. Nguyen, John E. Shaver, Brian J. Wesselman
  • Communications receiver with an adaptive squelch system
    Patent number: 5465404
    Abstract: A wireless communications receiver having an adaptive squelch system and operable in multiple states including a receiver (11) that provides a received signal when operating in a clear (unscrambled) state and when operating in a secure (scrambled) state; a squelch function (13) that generates an unsquelch signal when the received signal satisfies a quality level; and a controller (15) that sets the quality level to a predetermined level that corresponds to the receiver operating state.
    Type: Grant
    Filed: January 29, 1993
    Date of Patent: November 7, 1995
    Assignee: Motorola, Inc.
    Inventors: Michael H. Retzer, Alan D. Muehlfeld
  • Method for providing hand-offs in a frequency hopping communication system
    Patent number: 5446769
    Abstract: A method for handing off user devices (131-134) between network control processors (110, 120) in a frequency hopping communication system (100) includes establishing a set of synchronization frequencies (A-D) for use by said NCPs (110, 120), informing the plurality of user devices (131-134) of said synchronization frequencies (A-D) and assigning a synchronization frequency (A, B, C or D) to each respective NCP, each NCP transmitting synchronization information at its assigned synchronization frequency (A, B, C or D) during each hopping dwell (1-82). Upon a determination that a user device hand-off is necessary, said user device in question (133) tunes to a synchronization frequency (B) different from the synchronization frequency (A) employed by the currently serving NCP (110) and synchronizes its operation to the NCP (120) transmitting synchronization information on the tuned to synchronization frequency (B).
    Type: Grant
    Filed: March 4, 1994
    Date of Patent: August 29, 1995
    Assignee: Motorola, Inc.
    Inventors: John Shaver, Michael P. Nolan, Charles D. Macenski, Alan D. Muehlfeld, Brian Wesselman