Design Of Quality Measurement System Based On Three Terminal Fluxgate Sensor

Magnetic nanomaterials have many excellent physical and chemical properties, makingit successful applications in magnetic biosensors, and has been widely used in many fieldsimmunity test, disease diagnosis, environmental monitoring, food industry and so on. Thetraditional measure for these areas are mainly using magnetic quality quartz crystalmicrobalance (QCM) sensor, which is very sensitive to changes in its surface quality, and thequality of the signal is converted into a signal which can change the frequencycharacterization of magnetic quality. However, this approach requires measuring thedeposition reaction, not suitable for real time measurements. By analyzing the magneticproperties of magnetic nanoparticles combined with the advantages of low-frequencymagnetic flux gate sensors measure weak magnetic field, the design of the doubledifferential probe measuring weak magnetic flux gate sensor systems for the detection ofmagnetic nanoparticles quality.First, the principle of the core components of the three-terminal type magnetic flux gatesensors measuring the flux gate sensor system carried out a detailed theoretical analysis, andon three-terminal type fluxgate probe characteristics and traditional similarities anddifferences were analyzed and compared. And on this basis, given the overall structure ofdifferential fluxgate magnetic sensor measuring system, respectively, then the excitationfield from the Helmholtz coil design, the mechanical sensor in the system design, the sensorinterface circuit and the external data acquisition four aspects of the system architecture ofthis sub-section. The core of the whole system is a three-terminal type fluxgate sensorexternal interface circuit design, this thesis from the excitation of the circuit module, thesensing portion of the three major aspects of circuit modules and power modules arediscussed, each part shows the corresponding the circuit diagram, and on one of the key modules such as filtering circuit, phase shifting circuits, etc. were discussed in detail.Finally, in the data processing stage, the data acquisition system uses a producer-consumer parallel system. Before the first experiment in the test precision magneticshielding apparatus in the absence of a magnetic sensor of the offset correction circuit, andthe mechanical orientation of the probe to be adjusted. Finally, the quality of magneticmaterials and testing different DC voltage corresponding to the data value in differentdirections. By analyzing the data processing to establish a linear relationship between thetwo fitting measurement data analysis shows that the system design meets the requirements.