The Design Of Flux Locked Loop And The Method Of MCG Signal Separate

The magnetocardiogram measurement technology as the most important weak magnetic field detection application that is based on the Direct Current Superconducting Quantum Interference Device (DC SQUID). Due to its non-contact character, Magnetocardiagram(MCG) compared with Eletrocardiogram (ECG), not only it can reflect the body surface current change, but it can reflect electrical activity within the heart.MCG can reflect the intrinsic quality of the heart that provide more illness's information when medical science workers diagnose.According to requirement of application and the design indices,we divided this paper into two parts.The first part is the hardware design and test.According to the traditional FLL(Flux Locked Loop) Magnetocardiogram Measurement System.We proposed the improvement direct readout FLL Magnetocardiogram Measurement System.The FLL is the most important parts of this system. We used PSPICE simulation software based on theory,we verified this system has expansibility and feasibility in theory and technique.Firstly,we designed the hardware circuit.and verifying this system if can test the magnetic,and this system whether it can reach the requirement for application.The experiment results show that this system can immediately test the magnetic change.The output of system is linear with the input signal.And we measure the loop delay between input signal and output signal.Based on the relation between the loop delay and 3dB bandwidth.After testing,the 3dB bandwidth of this system can reach 54.1KHz.and it can reach the requirement for application.After finishing the hareware design and test,the second part of this paper is MCG signal separate.We use real MCG date which is provided by Tokyo Denki University.The experimental date of MCG contained the MCG signal, MMG signal and the industrial frequency signals.For removing the noise signal among of the date.Combining Blind Source Separation method,we first attempt to use EFICA to separate the MCG data.By contrast with the JADE and FastICA.And the simulation results show that the EFICA has better performance than JADE and FastICA.The MCG signal has better characteristic when we use EFICA.It has more information about human heart.This paper finished the hardware design and separate the MCG signal that provide the important experimental data and testing results.It has been an important theoretical foundation for hareware design and software build.