Study Of Imaginary Component Measurement System In Frequency Domain

In this paper,a shallow frequency domain electromagnetic virtual component detection instrumentation system is studied,which adopts a small self-return line frequency domain sensor to achieve direct measurement of secondary magnetic field through automatic electromagnetic compensation;and the system prototype is completed based on the idea of virtual instrument development.The research work starts from the basic principle of electromagnetic method exploration,and analyzes the expression of the relationship between frequency domain and time domain electromagnetic field;adopts the one-dimensional orthogonal evolution of the frequency domain response of the horizontal circular return line source to analyze the detection depth of the self-return line sensor,and determines the indicators and parameters of the sensor through the numerical simulation calculation and simulation of the sensor detection depth under different conditions;in order to improve the extraction quality of the secondary field signal,proposes a secondary field The algorithm can improve the filtering capability of digital orthogonal vector lock-in amplifier with higher flexibility,lower cost,higher scalability,portability and convenience of data processing and analysis,and can obtain higher resolution and higher signal-to-noise ratio by combining data sampling algorithm and limit-average filtering algorithm,so as to extract the amplitude and phase which are closer to the real value,and then The virtual component is extracted from the amplitude and phase.After the breakthrough of the key technology,the prototype was developed based on the virtual instrumentation scheme.The hardware of the instrument system includes a high-speed data acquisition card and operational amplifier as well as a self-return line sensor;the software mainly includes data acquisition,filtering,display and storage,and its algorithms mainly include waveform generation,signal emission and acquisition,signal digital orthogonal vector detection technology and limiting average filtering technology.The experimental test work has been carried out using the developed prototype,which shows that the performance of the detection system is reliable,the algorithm is correct and efficient,and the results of the research work are important for promoting the development and progress in the fields of archaeology,urban exploration,and UXO disposal.