Research On Measurement Technology Of Rock Core Electrical Spectrum Of Mixing Signals

The core has a dispersion characteristic,when the frequency of the measurement signal changes,the complex resistivity of the core also changes.In addition,the complex resistivity of the core is affected by the saturation of the contained core.When the saturation of the oil increases,The complex resistivity's amplitude of the core will also increase and the degree of dispersion will increase.This method can effectively evaluate the core oil content.In this paper,an instrument that can measure the core at the same time and under the same environment using a mixed signal is designed.The measurement results have the advantages of less time spent and less external interference.I first studied the method of generating mixed signal,and studied the mechanism of DDS technology during the design.And I finally determined to take use of DDS technology to produce the 1k,3k,10 k,30k,100 k,300k,500 k,1M,3M,10 M ten kinds of Frequency signals which compose the mixed signal needed;This design analyzes the frequency of the experimental signal,and gets the conclusion that the use of electrodes can achieve the measurement and transmission of the signal between 1k-10 M.After analyzing the method of generating the mixed signal,the FPGA-based DDS is selected.The signal generator design scheme;followed by the design of the transmitting circuit and the receiving circuit,and the simulation of the key part of the circuit and the schematic and PCB drawing,the production of a physical circuit board,completed the commissioning work;and finally I use the instrument to the actual core make measurements and get better results.