How to improve the quality and clarity of the sound that is played by the telephone device and the telephone equipment

摘要

PROBLEM TO BE SOLVED: To perform the equalization of digital telephone, especially, mobile telephone. ;SOLUTION: The equalization of tone to be reproduced due to an equalizer 4 is changed corresponding to the operating state of telephone. The information concerning that state can be provided by monitoring a volume 19 set by a user, measuring a background noise 17 in the operating environment of telephone through a microphone 9 of telephone and/or monitoring quality 16 of connection between the telephone and a communication network. The emphasis on the side of low frequency is weakened in the extremely noisy environment but strengthened in the quiest environment. It is profitable this telephone is the mobile telephone of digital cellular communication network.;COPYRIGHT: (C)1997,JPO