Patents Assigned to Oki Telecom, Inc.
  • Patent number: 5732347
    Abstract: A cellular telephone, in its most preferred embodiment, performs a method for notifying a digital cellular telephone user of an imminent communication disconnection. The preferred method includes, at least, generating at least one condition indication representative of at least one communication condition, analyzing the condition indication, determining whether a communication disconnection is imminent, enhancing quality of received communication signals when possible, and notifying the user of an imminent communication disconnection. Exemplary condition indications include, at least, continuous count and rate indications of frame checksum errors, insufficient quality frames, symbol errors, and chip errors, output power level indication, received signal strength indication, soft handoff status indication, other pilot signal indication, and current pilot signal strength indication.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: March 24, 1998
    Assignee: Oki Telecom, Inc.
    Inventors: Alden S. Bartle, George D. Erickson
  • Patent number: 5722068
    Abstract: A cellular telephone, in its most preferred embodiment, performs a method for notifying a digital cellular telephone user of an imminent communication disconnection. The preferred method includes, at least, generating at least one condition indication representative of at least one communication condition, analyzing the condition indication, determining whether a communication disconnection is imminent, enhancing quality of received communication signals when possible, and notifying the user of an imminent communication disconnection. Exemplary condition indications include, at least, continuous count and rate indications of frame checksum errors, insufficient quality frames, symbol errors, and chip errors, output power level indication, received signal strength indication, soft handoff status indication, other pilot signal indication, and current pilot signal strength indication.
    Type: Grant
    Filed: January 26, 1994
    Date of Patent: February 24, 1998
    Assignee: Oki Telecom, Inc.
    Inventors: Alden S. Bartle, George D. Erickson
  • Patent number: 5697081
    Abstract: A variable attenuator circuit provides variable attenuation responsive to received signal strength in a receiver to reduce intermodulation (IM) distortion. In a dual-mode frequency modulation/code division multiple access (FM/CDMA) cellular telephone implementation, the variable attenuator circuit decreases IM distortion by variably attenuating received radio frequency (RF) signals before an initial RF amplification stage to reduce the level of undesirable frequency mixing products. The variable attenuator circuit is turned on (activated) and off (deactivated) at a single, relatively low, input power level. An attenuator enable signal is also supplied from a logic unit of the mobile station to enable operation of the variable attenuator circuit throughout operation in a digital mode.
    Type: Grant
    Filed: December 13, 1995
    Date of Patent: December 9, 1997
    Assignee: Oki Telecom, Inc.
    Inventors: Robert L. Lyall, Jr., Richard I. Bain
  • Patent number: 5689815
    Abstract: An output power control system prevents saturation by limiting total output power and maintaining closed loop responsiveness for a radio telephone having closed loop and open loop gain control systems. The output power control system determines when total output power exceeds an output power trigger level and automatically enters a saturation prevention mode whereby total output power is reduced through modification of a closed loop power control register. In one embodiment, an output detector and an output comparator continuously monitor output power, and in another embodiment, an analog-to-digital converter samples output power levels.
    Type: Grant
    Filed: May 4, 1995
    Date of Patent: November 18, 1997
    Assignee: Oki Telecom, Inc.
    Inventors: Ryo Yamazaki, Anthony B. Waldroup, He Feng Wang