| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an audio system in which the output of a sub speaker can be prevented from exceeding a maximum output even when the audio system is used for a sub amplifier which amplifies a sub channel signal outputted from the sub speaker, without stabilizing a sub power supply voltage to be extracted from the same transformer together with a main power supply voltage. <P>SOLUTION: The audio system includes a power supply circuit 8 which supplies a stabilized main power supply voltage to a main amplifier and supplies a sub power supply voltage extracted from the same transformer as the main power supply voltage to a sub amplifier, and the maximum voltage value of a sub channel signal inputted to a sub amplifier 6 is limited by an ALC circuit 7. If the gain of the sub amplifier 6 is A multiples, the maximum output of the sub speaker is B watts and impedance is C ohms, the level of the sub channel signal is limited within the range of ±√BC*1/A. <P>COPYRIGHT: (C)2008,JPO&INPIT |
