Patents Represented by Attorney Kevin A. Buford
  • Patent number: 5504457
    Abstract: This invention relates to a pulsed power amplifier 100 for amplifying radio frequency signals. The pulsed power amplifier comprises control means 124, 126, 102 for generating control signals to control the amplifier output power so as to provide an output power pulse having rising and falling transitional phases, and means 112, 114, 117, 118, 122, 132, 134, 137, 138, 142 for generating a subsidiary pulse signal to be applied to the control means in order to adjust a transitional phase of the output power pulse. The generation of the subsidiary pulse may depend on a measured parameter of a previous output power pulse, such as the time taken for a preceding output power pulse to reach a predetermined output power level. Alternatively, the generation of the subsidiary pulse may depend on a parameter of the present output power pulse. In both cases the generating means can control the magnitude of the subsidiary pulse in response to the parameter.
    Type: Grant
    Filed: March 8, 1993
    Date of Patent: April 2, 1996
    Assignee: Motorola, Inc.
    Inventor: Ole Jensen
  • Patent number: 5485163
    Abstract: A system and method for locating a portable locator device in a communications network. The portable locator unit (PLU) (4) is activated either by an external signal (62) generated in response to remote activation source, such as a subscriber (6, 8) or PLU detector (106, 108), or by an internal activation signal triggered e.g. by the wearer. Once activated, the PLU (4) transmits a location signal (66). This location signal (66) is received by one or more network service nodes (20, 22, 24) which forward the information along with identifying service node information to a network location processor (26, 28). After having determined the location of the PLU (4) from the received information, the network location processor (26, 28) forwards this information to a designated source, such as the requesting subscriber or other authorized user (6, 8).
    Type: Grant
    Filed: March 30, 1994
    Date of Patent: January 16, 1996
    Assignee: Motorola, Inc.
    Inventors: Martin H. Singer, Daniel Tell, Anthony Kobrinetz
  • Patent number: 5467382
    Abstract: A system for clone detection within a communication system includes a message generator for generating a message to a subscriber having a first identifier and forwarding the message for transmission over plural communications channels, a memory for receiving and storing a response to the message from each subscriber using the first identifier, and a processor for determining if an unauthorized subscriber is using the first identifier from the stored responses to the message.
    Type: Grant
    Filed: May 31, 1994
    Date of Patent: November 14, 1995
    Assignee: Motorola, Inc.
    Inventor: Eric R. Schorman
  • Patent number: 5455863
    Abstract: Radio frequency based cellular telecommunication systems often require both subscriber units and communication units of a fixed network communication system to maintain secret data which may be used to verify authenticity as well as provide encrypting variables for message encryption processes. An efficient real-time authentication method and apparatus are provided which use a single message to provide authentication and communication link setup information. Further, an authentication method and apparatus are provided which uses instant-specific information such as a time of day, radio frequency carrier frequency, a time slot number, a radio port number, access manager identifier, a radio port control unit identifier, or a base site controller identifier to enhance the reliability of the authentication process.
    Type: Grant
    Filed: June 29, 1993
    Date of Patent: October 3, 1995
    Assignee: Motorola, Inc.
    Inventors: Daniel P. Brown, Louis D. Finkelstein, Jeffrey C. Smolinske
  • Patent number: 5455829
    Abstract: A method of de-interleaving ISDN channels for an information signal transceived through an ISDN interface.
    Type: Grant
    Filed: March 7, 1994
    Date of Patent: October 3, 1995
    Assignee: Motorola, Inc.
    Inventor: Jeffrey W. Klingberg
  • Patent number: 5444418
    Abstract: A feedforward distortion minimization circuit includes a first loop with an input splitter and first and second signal paths, each signal path having an amplifier. An output combiner couples the two signal paths and has an output signal path and an output dump load path. A first signal detector on the dump load path detects a dump load signal, and in response a gain and phase controller operates to adjust the gain and phase of a first signal on one of two signal paths to minimize the power delivered to the dump load. The feedforward circuit also includes embodiments in which both amplifiers operate at around the same power amplification level, and in which a second loop has an error amplifier for further distortion correction.
    Type: Grant
    Filed: July 29, 1994
    Date of Patent: August 22, 1995
    Assignee: Motorola, Inc.
    Inventor: James E. Mitzlaff
  • Patent number: 5432780
    Abstract: A cellular radiotelephone communication system cell site equipment is provided. The cell site equipment includes a radio frequency transmitter operating as one signal frequency source. In addition, the cell site equipment includes a first and a second signal combiner device tuned to a first and a second signal frequency, respectively. Further, the cell site equipment includes a radio frequency switching mechanism, operatively coupled to the radio frequency transmitter, the first signal combiner device, and the second signal combiner device, for coupling the radio frequency transmitter to either of the first and the second signal combiner devices. In one embodiment, each signal combiner device includes a resonant cavity for isolating a signal frequency source from other signal frequency sources and a coupling for coupling the isolated signal frequency source to a common transmitter output.
    Type: Grant
    Filed: April 19, 1993
    Date of Patent: July 11, 1995
    Assignee: Motorola, Inc.
    Inventors: John M. Smith, James F. Long, Ronald J. Wanat, Anthony Kobrinetz
  • Patent number: 5428504
    Abstract: A cooling cover for an RF power amplifier device having a mounting support, a first lead, and a heat generating die mounted on the first lead. The cooling cover is comprised of a body of a thermally conductive material and having a first surface and a second surface. A layer of thermally conductive and electrical non-conductive material is deposited upon the second surface of the cooling cover. When the cover is coupled to the mounting support, the first surface is in contact with the mounting support and the second surface is in contact with the first lead thereby providing a low resistance heat path between the heat generating die and mounting support.
    Type: Grant
    Filed: April 9, 1993
    Date of Patent: June 27, 1995
    Assignee: Motorola, Inc.
    Inventor: Ravinder N. Bhatla
  • Patent number: 5428647
    Abstract: A method and apparatus is provided for synchronizing a received communication signal. A synchronization signal is derived from a received signal having a plurality of synchronization words. Each synchronization word has a predetermined number of synchronization symbols. The synchronization signal is filtered. The filtering is characterized by spacing each filter tap to correspond to synchronization word length increments. Synchronization information is generated which is based on a comparison of the filtered synchronization signal to a threshold. Finally, the synchronization information is output based on a confidence derision derived from the synchronization information.
    Type: Grant
    Filed: December 7, 1992
    Date of Patent: June 27, 1995
    Assignee: Motorola, Inc.
    Inventors: Phillip D. Rasky, James F. Kepler, Gregory M. Chiasson
  • Patent number: 5428818
    Abstract: A method and apparatus is provided for reducing interference in a radio communication link from a central site (230) to a mobile unit (228) in a cellular communication system. The central site (230) includes a first (202) and a second (216) antenna which serve the geographic region (214) in which the mobile unit (228) is located. The radio communication link may be provided by communicating a signal in a first radio communication channel between the first central site antenna (202) and the mobile unit (228). Similarly, the radio communication link may be provided by communicating a signal in a second radio communication channel between the second central site antenna (216) and the mobile unit (228). A measure of interference in the first radio communication channel providing the radio communication link is determined. The radio communication link is switched, in response to the measure of interference being above a predetermined threshold, from the first to the second radio communication channel.
    Type: Grant
    Filed: January 18, 1994
    Date of Patent: June 27, 1995
    Assignee: Motorola Inc.
    Inventors: Reuven Meidan, Noam Livneh, Giora Silbershatz, Mordechai Ritz
  • Patent number: 5418813
    Abstract: A method and apparatus is provided for creating a composite waveform. This composite waveform is created by coding a plurality of input digital information signals. Subsequently, the plurality of coded input digital information signals are communicated over a communication medium to a digital combiner. The digital combiner combines the plurality of coded input digital information signals. Finally, the digitally combined information signal is spectrally shaped to form a composite waveform. These composite waveform creation principals may be applied to digitally encoded voice subbands in a subband coding system as well as channel information in a direct sequence code division multiple access (DS-CDMA) communication system transmitter.
    Type: Grant
    Filed: December 6, 1993
    Date of Patent: May 23, 1995
    Assignee: Motorola, Inc.
    Inventors: Terry M. Schaffner, Michael D. Kotzin, Anthony P. Van den Heuvel
  • Patent number: 5414378
    Abstract: A method and apparatus is provided for resetting an electronic device in response to a voltage transient. The apparatus implements the method steps of detecting the transient at an input to, and receiving an output from, a voltage sensing circuit in response to the transient. The method also includes the step of providing an electronic device reset signal at the output of the voltage sensing device by clamping the input of the voltage sensing circuit to the output of the voltage sensing circuit through an interconnected positive feedback clamping capacitor. Timing capacitors are used to extend the duration of the reset pulse.
    Type: Grant
    Filed: June 4, 1992
    Date of Patent: May 9, 1995
    Assignee: Motorola, Inc.
    Inventors: Gregory A. Edgar, Dan Huslig
  • Patent number: 5392044
    Abstract: A method and apparatus are provided for digitizing a wide frequency bandwidth signal (105). The digitizing is accomplished by separating the wide frequency bandwidth signal (105) into a plurality of narrow frequency bandwidth signals with a plurality of filters (110). Subsequently, a converter (120) generates digitized samples of the narrow frequency bandwidth signals. Finally, a composite digitized signal (160) is generated by a combiner (150) from the digitized samples which substantially represents the wide frequency bandwidth signal (105).
    Type: Grant
    Filed: March 8, 1993
    Date of Patent: February 21, 1995
    Assignee: Motorola, Inc.
    Inventors: Michael D. Kotzin, Joseph J. Schuler
  • Patent number: 5392300
    Abstract: A dual mode radio communication unit for a digital communication system is provided having an error controller including an error detection encoder and a forward error correction encoder which encode an input information signal into an error protected data bit stream. In addition, the communication unit includes a mode selector which enables either the error detection encoder or the forward error correction encoder used with a particular mode of operation of the communication unit. Further, a corresponding dual mode radio communication unit is provided having an error controller for generating estimated information signal samples according to a group of algorithms consisting of either an error detection algorithm or an error correction algorithm. In addition, the corresponding communication unit includes a mode selector for receiving a signal according to a particular one of the group of algorithms which is associated with a particular mode of operation of the corresponding communication unit.
    Type: Grant
    Filed: November 10, 1992
    Date of Patent: February 21, 1995
    Assignee: Motorola, Inc.
    Inventors: David E. Borth, John R. Haug, Phillip D. Rasky, Gregory M. Chiasson
  • Patent number: 5383202
    Abstract: A method is provided of attenuating a signal value within erroneous frames of a logarithmically coded digital signal. The method includes the steps of detecting an erroneous frame of the logarithmically coded digital signal and adding an attenuation value to a frame exponent of the erroneous frame.
    Type: Grant
    Filed: November 25, 1992
    Date of Patent: January 17, 1995
    Assignee: Motorola, Inc.
    Inventors: Gregory A. Edgar, Jeff Klingberg, John Ruppel
  • Patent number: 5365585
    Abstract: A method and apparatus for generating a pseudo-random bit sequence is provided. A first input bit is determined as a function of bits stored in a shift register in accordance with a first feedback algorithm. In addition, a second input bit is determined as a function of bits stored in the shift register in accordance with a second feedback algorithm. Subsequently, a particular input bit to be provided to the shift register is deterministically selected from the group consisting of the first input bit and the second input bit such that a non-linear pseudo random sequence may be produced by the shift register. In addition, a communication unit which utilizes the pseudo-random bit sequence in encrypting a signal to be transmitted and decrypting a received signal is described.
    Type: Grant
    Filed: August 30, 1993
    Date of Patent: November 15, 1994
    Assignee: Motorola, Inc.
    Inventors: Larry C. Puhl, Louis D. Finkelstein
  • Patent number: D352941
    Type: Grant
    Filed: November 23, 1993
    Date of Patent: November 29, 1994
    Assignee: Motorola, Inc.
    Inventor: Albert M. Bolton, Jr.
  • Patent number: D367652
    Type: Grant
    Filed: May 2, 1995
    Date of Patent: March 5, 1996
    Assignee: Motorola, Inc.
    Inventor: Thomas G. Beaumont
  • Patent number: D367859
    Type: Grant
    Filed: February 28, 1995
    Date of Patent: March 12, 1996
    Assignee: Motorola, Inc.
    Inventors: Thomas G. Beaumont, Neill Butcher
  • Patent number: D368477
    Type: Grant
    Filed: April 26, 1995
    Date of Patent: April 2, 1996
    Assignee: Motorola, Inc.
    Inventors: Vera Curtis, Anthony Ryan