Ericsson Gmbh

Peter J Doherty

Ronald D Boesch

Darrell G Epperson

The present invention relates to a method and apparatus for providing a radio frequency output to promote higher amplifier efficiencies. In one embodiment, the apparatus includes a driver and a switch that alternately connects first and second circuit paths to the driver and an antenna. A power amplifier having a first bias lead lies in the second circuit path. When low power is required, the switch connects the first circuit path to the antenna, and disconnects the first bias lead from a bias. When high power is required, the switch disconnects the first circuit path from the antenna, and connects the second circuit path and the first bias lead to the antenna and the bias, respectively.

Method and apparatus for attaining higher amplifier efficiencies at lower power levels

Power control circuitry for the transmitting section of a mobile terminal provides gain control for amplifiers operating at different frequencies. Preferably, one amplifier controls the signal gain the signal transmission path in the IF section and another amplifier controls gain in the signal transmission path in the radio frequency (RF) section. One variable gain amplifier may be controlled based on the strength of the received signals while the other may be controlled based on commands from the base station and/or calibration and alignment settings during manufacturing. In addition, one or both of the amplifiers may optionally be controlled in whole or in part based on calibration and/or alignment settings established during manufacturing. Preferably, the gain control signal based on received signal strength is analog based and the control signal received from the control system is a pure digital signal substantially immune to noise. In such an embodiment, the corresponding amplifier is configured to receive a digital value and provide a corresponding amplifier gain.

Power control for wireless communications system

An apparatus for providing an antenna impedance matching network that does not include mechanical switch contacts is disclosed. A retractable antenna includes a conductive plate moveable between the extended and retracted positions of the antenna. When the conductive plate is located in the extended position an impedance matching circuit responsive to the position of the conductive plate is connected between the antenna and an amplifier of a radio telephone. In response to location of the conductive plate in the retracted position, the impedance matching circuit is shorted out such that the antenna is connected directly to the amplifier via a capacitive effect between the conductive plate and a conductive coil of the shorted out impedance matching circuit.

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Apex, NC, United States of America

Peter J Doherty