Design of distributed synchronous acquisition system of seam seismic data

In order to synchronize various collection terminals with each other and synchronize two- channel in the same collection terminal in acquisition system of seam seismic data，a distributed two-channel synchronous acquisition system of seam seismic data was designed. The system applies a weak signal conditioning circuit to improve signal-to-noise ratio of seismic signal, and uses eight-channel synchronization sampling core to realize synchronization sampling of two-channel in the same collection terminal．A clock synchronization system is constructed which is composed of GPS receiver, digital phase lock loop and STM32 main controller. The adaptive oscillator model drift correction algorithm is used to predict and estimate temperature-drift characteristic and aging characteristic of oven controlled crystal oscillator, so as to realize clock synchronization and time synchronization of various collection terminals in coal mines. The test results show that the system realizes distributed synchronous acquisition of multi-channel seismic signal, the accuracy of synchronization between the different data collection terminals is better than 10 μs within 8 hours continuous work in underground coal mine.