| 摘要 |
PROBLEM TO BE SOLVED: To notify a user in using a portable terminal with an earphone of approach of a person or an object around the user.SOLUTION: If a person or an object generating sound approaches in environment where a user uses an earphone of a cellular phone and external sound is intercepted, a sensor built in the cellular phone detects a sound frequency. At the time, the cellular phone automatically controls volume of sound listening with the earphone to fade out the sound (gradually reduce the volume) and sends alarm notification sound to the user. Further, the cellular phone determines which object approaches by difference in the sound frequencies and notifies the user of an alarm on a screen of the cellular phone. Further, the cellular phone detects change in the frequencies by using the principle of Doppler effect and outputs the alarm only to the object increasing the sound frequency. |
