A HIGH-PRECISION SYNCHRONOUS SAMPLING APPROACH FOR LARGE-SCALE DISTRIBUTED WIRE SENSOR NETWORKS IN SEISMIC DATA ACQUISITION SYSTEMS

In large-scale land or marine seismic data acquisition systems, a multinode distributed wire sensor network structure is still presently the main choice. Synchronous sampling between each node in such systems is very important, which may significantly influence the results of the ensuing data analysis. A synchronous sampling approach with its implementation is introduced in this article. The main idea of this approach is combined command delay compensation with clock phase compensation of CDR (clock data recovery) to achieve high precision of synchronization. For testing, a kind of six-node land seismic data acquisition system with 100 m distance between two neighboring nodes is successfully developed using this approach. Test results indicate that the achieved precision of synchronous sampling is fixed after power-on with no time accumulation effect; the sampling clock phase difference between two neighboring nodes is maximally 1 ns in the worst case, and the command synchronization error among all the nodes is less than 1 ns independent of the number of nodes and the distance between nodes. High synchronous precision is much more significant for the shallow stratum engineering seismic exploration, because shallow exploration always needs high sampling rates; for example, 32 kilo sample per second, and hence the tolerant synchronization error is much smaller.     

“金银花”CAD／CAM系统数据集成平台研究

首先简要介绍了基于ＳＴＥＰ的ＣＡＤ／ＣＡＭ 集成制造系统———“金银花”的体系结构，着重论述了金银花系统的集成平台──“蜜蜂”产品数据管理系统的主要功能、关键实现技术及系统的特点，最后进一步探讨了“蜜蜂”产品数据管理系统的发展方向     

基于LabWindows/CVI的传输带激光测速系统设计

介绍了固体表面激光相关实时测速的原理。根据这一原理,设计了基于LabWindows/CVI开发平台的传输带激光互相关实时测速系统。详细阐述了LabWindows/CVI平台下测速系统的数据采集、数据处理模块、数据显示更新、测量参数设置等模块的设计。经过实际测试,验证了测试系统的可行性、实用性。