| 摘要 |
PROBLEM TO BE SOLVED: To make possible an operation for superimposing various audio signals such as a voice, music and a calling signal by providing an on-chip resolution measure in which spatial saving and cost effects are improved for an audio output apparatus. SOLUTION: The audio superimpose includes two or more audio input channels, configuration of switches 35 and 36 for driving different input audio signals 31 and 32, configuration of resistors 33 and 34 with respect to respective input lines for audio signals, and an inverted voltage amplifier 40 as an output stage having an input and output for controlling the superimposed audio signals. The input is coupled with a reference voltage 44, and the audio signals are superimposed by the operated switches. The output is available for operating a loudspeaker. A circuit includes an input resistor 41 for the voltage amplifier and a means 42 for setting a gain of the amplifier of the output stage. COPYRIGHT: (C)2004,JPO
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