U.S. Philips Corporation

Hendrik A Visser

Lukas Leyten

Petrus G Baltus

Antonius G Wagemans

Jan Van Sinderen

Antoon M Tombeur

An amplifier circuit, particularly for RF-purposes includes a main current stream of a controllable RF-semiconductor device having a control input, a control means having a control output coupled to the control input for controlling the main current stream, and a compensation circuit having a compensation output coupled to the control input for compensating the controllable semiconductor device. The compensation circuit is constructed so as to be temporarily active during a period of time wherein the control means do not supply a control output signal to the control input of the controllable semiconductor device. This provides a suitable solution for IC's and for dealing with DC-adjustment disturbances in a low DC-current dissipating manner caused by a lack of pull-down capability when the amplifier circuit operates at very high frequencies or at relatively large amplitudes.

Amplifier circuit, a transmitter and a wireless telephone

A radio transmission system is disclosed for operating in a multipath transmission environment having improved reception, and in the case of bi-directional systems, also improved transmission. This is achieved by using at least two reception beams, corresponding to one fixed reception beam and one scanning reception beam, and by continuously evaluating the quality of these beams as to their signal-to-noise-and-interference ratios or bit-error-rates (BERs). The best beam is dynamically chosen to be the fixed beam. Alternatively, the fixed beam is updated with the best beam acquired by the scanning beam as compared to the current fixed beam. In a bi-directional system, the receiving radio apparatus applies the direction of the best reception beam for transmission to the opposite radio apparatus.

Radio transmission system and a radio apparatus for use therein

A radio transmission system comprises a phased-array radio apparatus for optimizing reception in a multipath transmission environment. In the phased-array radio apparatus, phase shifting is performed after down-conversion of received RF signals. Phase control and beam-forming are simple. By applying a zero-IF or low-IF receiver structure, the complete structure can easily be fully integrated.

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Eindhoven, Netherlands

Hendrik A Visser