Design of Signal Acquisition System Based on Earthquake Precursor Electromagnetic Disturbance

The seismic precursory data collecting system, which includes short-circuit noise, frequency band, and dynamic range, is an important link in the digitalization of seismic monitoring systems. The digital requirements of electromagnetic sensors for seismic precursor detection are met in this study by a high accuracy, low noise, and powerful embedding acquisition method. The low noise signal conditioning circuit is constructed based on the sensor's output voltage and bandwidth, and 1kHz sampling is achieved using a 24-bit high-precision ADS1256 analog-to-digital conversion chip, and the data is then communicated to the PC through the 485 bus. Finally, the acquisition system's noise level in the 0.5Hz~60Hz region is around −120dB, with a dynamic range of 133dB. The acquisition system is compared to the NI Company's 4431 acquisition system in order to validate its correctness. The findings reveal that the two systems work similarly, and the self-made acquisition system is significantly less expensive than the 4431 acquisition system.