Abstract: According to the measurement principle of the ocean current signal sensor, the technical scheme of the acquisition amplifier circuit was proposed. Aiming at the characteristics of large noise of the collected signal, the weak signal of the ocean current electric field was filtered and extracted, realizing the compensation amplification of the in-phase component of the signal. To a certain extent, it overcame the strong interference of the induced electric field caused by the sensor when it sank, and improved the accuracy of circuit measurement. At the same time, the principle of multi-stage amplification was adopted to amplify the weak signal to the observable range of the instrument. It is verified by Multisim simulation software that the acquisition amplifier circuit meets the design requirements and amplifies the signal to 105~106 times while ensuring the quality of the signal.

Key words: nanovolt level signal, amplification circuit, ocean current electric field, Multisim simulation