To simplify a configuration, and achieve a self-diagnosis function and an adjustment function in a sensor system for mainly processing an analog signal, especially a piezoelectric sensor system.

The piezoelectric sensor system includes a piezoelectric sensor 1 for outputting a voltage corresponding to a mechanical external force, an AC amplification means 5 for AC-amplifying an output from the piezoelectric sensor 1, a determination means 7 for determining the existence of the external force applied to the piezoelectric sensor 1 based on an output from the AC amplification means 5, and a delay means 3 for delaying the output from the piezoelectric sensor 1 for a predetermined delay period. The determination means 7 determines whether the piezoelectric sensor system is normal based on the output from the AC amplification means 5 for the delay period after the piezoelectric sensor system is powered.

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