| 摘要 |
PROBLEM TO BE SOLVED: To automatically increase the tone volume of a call tone stepwise without being offensive to the ear as time elapses from the an incoming call by controlling the tone volume, so as to be increased stepwise by multiplying an initial tone volume with a prescribed magnification at each desired time. SOLUTION: An oscillator 1 generates a call tone signal at the arrival of an incoming call. An amplifier 2 amplifies a signal from the oscillator 1 by an optional amplification factor through a gain change. A loudspeaker 3 sounds a call tone based on the output of the amplifier 2. A CPU 4 controls the gain of the amplifier 2 so as to increase stepwise the tone volume of the call tone automatically and so as to increase the tone volume gradually attended with count of an elapsed time after start of ringing. Thus, in the tone volume control, where the call tone rings while the tone volume of the call tone is stepwise increased as the lapse of time from the incoming call, the initial tone volume is multiplied with a prescribed magnification so that the tone volume is increased at each desired time thereby allowing the user to hear the tone volume as a natural increase to the ear.
|
