Abstract:To meet the needs of time accuracy testing of seismic digitizer, we use a specific circuit to extend the PPM(pulse per minute) output by the common reference clock source to a duty cycle of 50%. With the extended PPM, the time tag accuracy of seismic digitizer is tested at room temperature, constant low temperature and constant high temperature environments. We study the influence of ambient temperature on time tag accuracy. The results show that time tag accuracy and drift trend of seismic digitizer are affected by the change of ambient temperature. A temperature change of about 1 ℃ in half an hour can cause the time tag accuracy change of microsecond stage and the drift trend change of time tag delay. The cumulative effect of temperature change reflected by temperature to time numerical integration has good correspondence with the drift trend change of seismic digitizer. The time tag delay at constant temperature environment shows monotonous characteristics. The drift rate is determined by the crystal resonators used by individual digitizer, and it is associated with the ambient temperature.
YE Shishan,XIE Jianbo,CHEN Jie et al. Testing of Ambient Temperature Influence on Time Tag Accuracy of Seismic Digitizer[J]. jgg, 2022, 42(4): 431-435.