MOBILE COMMUNICATION TERMINAL, SYNCHRONIZATION JUDGING CIRCUIT USED IN THE MOBILE COMMUNICATION TERMINAL, CONTROL METHOD, AND SYNCHRONIZATION JUDGING CONTROL PROGRAM

摘要

An object of the present invention is to disconnect communication as soon as possible for reducing power dissipation when it is decided that it will take long to determine if the local spread code and the reception spread code are synchronized on a mobile communication terminal that employs Code Division Multiple Access. When it is decided that the common channel level 'a' is equal to or higher than a third threshold (common channel level threshold), an RLF decision control unit 16 compares the SIR data 'd' with a first threshold and a second threshold to decide in sync state or out-of sync state between the local spread code and the reception spread code and outputs the decision signal 'e'. In particular, when it is decided that the common channel level 'a' is lower than the third threshold, the first threshold and the second threshold are set to the same value. In this state, when it is decided that the level of the SIR data 'd' is lower than the first threshold (=second threshold), the decision signal 'e' corresponding to an out-of sync state is output immediately after a predetermined delay time elapses. So, the power dissipation is reduced.