Patent ID: 7555132

Claim:
An apparatus for adjusting sound volume for an audio system, the apparatus comprising: a controller connected to an amplifier of the audio system for controlling amplification of the amplifier, the controller comprising a microprogrammed control unit (MCU); and a first circuit for adjusting the sound volume, the first circuit comprising: an attenuation circuit for attenuating input audio signals, the attenuation circuit comprising: a first resistance, one end of the first resistance being connected to a tuner of the audio system; a second resistance, one end of the second resistance being connected to another end of the first resistance, and another end of the second resistance being grounded; a third resistance, one end of the third resistance being connected to the other end of the first resistance; a first diode, the cathode of the first diode being connected to another end of the third resistance, and the anode of the first diode being grounded; and a second diode, the anode of the second diode being connected to the other end of the third resistance, and the cathode of the second diode being grounded; and a first switch, an input end of the first switch being connected to the tuner of the audio system and the other end of the first resistance, and an output end of the first switch being connected to an audio processor of the audio system.