| 摘要 |
PROBLEM TO BE SOLVED: To control amplification factor, based on the maximum amplitude voltage of an inputted audio signal, in a volume control unit. SOLUTION: The volume control unit comprises an amplification factor control means for controlling the amplification factor of an amplifying means for amplifying the audio signal; a maximum amplitude voltage detection means for detecting the maximum amplitude voltage of the audio signal; a power switch for switching the connection and disconnection of a power supply line; an amplification factor storage means for storing the amplification factor of the amplifying means, an upper-limit amplification factor storage means for storage, while the upper-limit amplification factor is made to correspond to the maximum amplitude voltage; and an amplification factor comparison means for comparing the amplification factor stored in the amplification factor storage means with the upper-limit amplification factor. If the amplification factor stored in the amplification factor storage means is less than and equal to or larger than the upper-limit amplification factor, when the power switch connects the power supply line, the amplification factor control means sets the amplification factor of the amplifying means to be an amplification factor read from the amplification factor storage means and the upper-limit amplification factor, respectively. COPYRIGHT: (C)2005,JPO&NCIPI
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