Precision Coherent Detection Of Transient Data Acquisition System

Data Acquisition" is not only the technical tool of measure and control, but also the important means of computer and communication. With the development of current science technology, the design of Data Acquisition System is need to be better than ever. As a set of excellent geophysics instrument, there must be a Data Acquisition System with high speed, high precision and great flexibility. Furthermore, it is important for us to enhance the precision and the ability of anti-noise because of the current industrial interference and cultural interference. In this paper, we put forward and carry out a kind of precision coherence detection instantaneous data acquisition system (PCD1DAS) successfully. High ability of anti-noise > good precision, great flexibility and high speed are its specialty.The realization of the PCDIDAS is described mainly in the paper, and the paper can be divided into three parts: first, the basic theory of PCDIDAS, and some results of experiment are described; secondly, there are some discussion about the realization of the PCDIDAS, including the hardware and software; last, some results of the model experiment are provided.In chapter two, the basic theory about the PCDIDAS is discussed in detail, and the PCDIDAS is brought forward. For example, the tri-frequency induced polarization method, the theory of the coherence detection and the basic theory of the DSP are described mainly.In chapter three, the hardware of the PCDIDAS is discussed carefully from three aspects. One is the hardware of the precision detection apparatus receiver; another one is interface circuit, and the last one is the issue of synchronization between the receiver and the transfer. It points out that the precision of Data Acquisition and the resolution power are improved because of the good design of hardware and the technology of synchronization with a common clock between the receiver and the transfer.The software design is discussed in detail in chapter four. The framework of applied program under DOS environment is put forward. The software is not only clear and friendly but also reliable. The operation of applied program is easy, and it can show data timely and all kinds of curves in time. The function and implement method of each module of the software system are given afterward. Auto/Manual calibration and Auto/Manual zero adjustment are also realized in the software system, thus the instrument turn to more convenient and applicable. Because the technology of overlapping and average is used in Data Acquisition, the quality of data acquisition isimproved.Some model experiments are given in chapter five. It points out that the PCDIDAS has the specialty of high precision and high resolution power.Finally, the conclusion of the whole paper is described.