METHOD AND CIRCUIT FOR AUTOMATIC TUNING OF AN ANTENNA CIRCUIT

摘要

An antenna circuit (A) is fed with a signal, to whose frequency it should be tuned. Its reactance changes stepwise according to an algorithm implemented in a controller (C). A voltage phases at terminals (1, 2) of an element (c0, c1,..., en; co) having the reactance of one kind are determined and the difference of said phases is determined. The reactance changes so many times that said phase difference approaches to p/2 closer than a tiniest phase difference is as can be set by said changing of the reactance. The achieved setting is stored as the setting of the antenna circuit tuned to said frequency. Tuning is carried out automatically and time-efficiently especially according to the first embodiment also in a simple way since no analogue-to-digital conversion is needed.