Motorola Corporation

John H Spears

Allen Wong

David L Bond

George W Meyer, Jr

Thomas F Vondrak

David M Schlueter

Wayne E Smith

Matthew R Greene

Keith R Manssen

A reference oscillator (118) in a communication device (100) such as a radiotelephone is controlled by temperature compensating the reference oscillator (118). At the time of manufacture, characterizing data are stored in non-volatile memory (128) in the communication device (100). When the communication device (100) is powered up, the characterizing data are read and used to provide an initial correction (206) to the output frequency of the reference oscillator (118). Subsequently, an automatic frequency control operation is performed using the RF signal received from a remote transmitter as a reference signal. A frequency correction is determined (214) in the form of a frequency step size and step direction. The output frequency of the reference oscillator is repeatedly stepped until frequency error is minimized.

Method and apparatus for temperature compensation of a reference

A cellular speakerphone (100) includes a housing (101) containing a transceiver circuit (203), a processor and switching circuit (205), a coupler (209), and a hands-free user interface (207). The processor and switching circuit (205) and the hands-free user interface (207) operate the cellular speakerphone (100) in a default hands-free mode that is automatically interruptable to permit the cellular speakerphone (100) to operate in a handset mode when an optional handset (127) is operably coupled to the cellular speakerphone (100) via the coupler (209).

Cellular speakerphone and method of operation thereof

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McHenry, IL, United States of America

John H Spears