| 摘要 |
PROBLEM TO BE SOLVED: To reduce the circuit scale, the cost and the power consumption by using a common filter for filter processing that is applied to an analog signal outputted from a D/A converter means to an input output common use terminal and also for filter processing that is applied to an analog signal outputted from the input output common use terminal to an A/D converter means. SOLUTION: In an input mode, a switch 203 and a switch 204 are both thrown to the position of a terminal (b). An analog signal received from an input output common use terminal 207 is outputted via the switch 204, an input amplifier 205 and the switch 203 to a filter 208, where an undesired band component is eliminated and the resulting signal is outputted to an A/D converter 202. In an output mode, the switches 203, 204 are both thrown to the position of a terminal (a). An analog signal outputted from the D/A converter 201 is outputted via the switch 203 to the filter 208, where undesired band component is eliminated and the resulting signal is outputted to the input output common use terminal 207 via an output amplifier 206 and the switch 204.
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