Development and Implementation of Low Noise Acquisition and High Precision Time Synchronization Technology for Shallow Buried Microseismic Monitoring System

Existing shallow-buried microseismic acquisition systems face significant challenges in deployment and maintenance, with noise performance often failing to meet the demands of modern microseismic detection techniques. Furthermore, these systems rely on internal clocks for timestamping, where frequency drift in crystal oscillators can result in substantial cumulative time errors. To address these limitations, this study develops a high-precision data acquisition channel by applying principles of minimum noise and impedance matching, alongside a comparative analysis of state-of-the-art ∆-Σ analog-to-digital converters (ADCs). The system achieves a short-circuit noise level below 1.5 μV @ 500 Hz, a dynamic range of 126.7 dB @ 500 Hz, and a signal-to-noise ratio (SNR) of 131.53 dB @ 500 Hz. Additionally, a high-precision time synchronization method is proposed, combining timestamp indexing and time interpolation to compensate for cumulative errors caused by ADC clock crystal drift. This method integrates a high-accuracy synchronization design based on GPS pulse-per-second (PPS) interrupts and GPS serial interrupts, achieving a synchronization accuracy of 0.688 μs between nodes.