Method for calibrating the frequency of an RF oscillator in a mobile part of a mobile communications device

A method is provided for calibrating the frequency of an RF oscillator in a mobile part of a mobile communications device when the mobile part is first switched on, wherein the method includes the steps of: sampling a modulated carrier that is transmitted by a base station and has a prescribed frequency accuracy, such that scanning of the modulated carrier is performed via a frequency search algorithm with the modulated carrier being demodulated, a signal thus demodulated being compared in an evaluation and synchronization program via a correlation with a sequence known in advance, and a correlation peak in an output of the correlator being determined; determining a frequency error between the frequency of the RF oscillator in the mobile part of the mobile communications device and a known channel frequency of the base station by comparing the determined correlation peak of the output of the correlator with a channel raster, known in advance to the mobile communications device, of the base station; synchronizing the mobile communications device with the modulated carrier; and adopting a frequency, corrected by the frequency error, for the RF oscillator as reference frequency for further calibration operations.