METHOD AND APPARATUS FOR AUTOMATICALLY TUNING AN IMPEDANCE MATRIX, AND RADIO TRANSMITTER USING THIS APPARATUS

摘要

The invention relates to a method and an apparatus for automatically tuning an impedance matrix, for instance the impedance matrix seen by the power amplifiers of a radio transmitter using a plurality of antennas simultaneously. The invention also relates to a radio transmitter using this apparatus. An apparatus for automatically tuning an impedance matrix has 4 user ports (112) (122) (132) (142) and 4 target ports (111) (121) (131) (141), and comprises: 4 sensing units (1); a signal processing unit (2), the signal processing unit estimating real quantities depending on the impedance matrix presented by the user ports, using the sensing unit output signals obtained for 4 different excitations applied successively to the user ports, the signal processing unit delivering a tuning instruction; a multiple-input-port and multiple-output-port tuning unit (3) comprising adjustable impedance devices; and a tuning control unit (4) receiving the tuning instruction from the signal processing unit and delivering tuning control signals to the multiple-input-port and multiple-output-port tuning unit, the reactance of each of the adjustable impedance devices being mainly determined by one or more of the tuning control signals.