AN ENVIRONMENTAL NOISE LEVEL ESTIMATION APPARATUS A COMMUNICATION APPARATUS A DATA TERMINAL APPARATUS AND A METHOD OF ESTIMATING AN ENVIRONMENTAL NOISE LEVEL

摘要

PURPOSE: To enable the sound device, which automatically control the quality and volume of its reproduced sound according to characteristics of ambient noise, and to precisely detect the noise by using a transmission microphone. CONSTITUTION: This device is equipped with a noise level detecting means 110, which detects the level of ambient noise through the transmission microphone 102 and a noise level updating means 111 which smoothly vary the detected noise level, when the level rises. If a voice reaches the transmission microphone 102, the voice level is higher than the noise level in its voiced section, which is utilized to output the level obtained by smoothly increasing the output value which is one sample precedent when the noise level rises or the noise level as is when the noise level falls, thereby speedily detecting variation in ambient noise characteristics without reacting to the voice.