摘要 |
A signal processing unit of the present invention includes: input terminal (21) to which an input signal is input; high-pass filter (23) for cutting off the DC component of the input signal; output terminal (22) for outputting a signal output from high-pass filter (23) as an output signal; determination element (26) for determining whether or not the voltage of the output signal falls out of a predetermined detection threshold range; and, switches (27,28) for connecting the output node of high-pass filter (23) to a power supply circuit when the voltage of the output signal is determined to fall out of the detection threshold range at determination element (26).
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