Signal conditioning circuit

The invention relates to the technical field of circuit design, and discloses a signal conditioning circuit, which comprises a test signal control circuit used for processing a test frequency signal according to a test enable signal and outputting the test frequency signal to a differential amplification circuit; the differential amplification circuit is used for amplifying an output signal of the test signal control circuit and a signal generated by an external sensor; the output circuit is used for processing and outputting an output signal of the differential amplification circuit; and when the external sensor does not work, the test enable signal is in an effective state, and whether the signal conditioning circuit, the external sensor and the sensor line have faults is judged according to whether the frequency of the output signal of the signal conditioning circuit is consistent with the frequency of the test frequency signal. Different signals are input through different ports of the differential amplif