The Signal Regulation System Of Electron Cyclotron Emission Imaging Diagnostic

This paper mainly introduces the hardware improvement of Electron Cyclotron Emission Imaging(ECEI),which includes two parts.On the one hand,we optimize the set of ECEI shielding and improve the shielding effectiveness.On the other hand,we have designed the remote control system which regulate the radio frequency input attenuator remotely.Besides,we developed a kind of radio frequency spectrometer,which can detect the frequency distribution of the plasma device's surrounding.The shielding box protect the ECEI system from the electromagnetic interference of Lower Hybrid Current Drive(LHCD).Through the experiment on EAST,we have affirmed the LHCD interference come from the EAST port.The shielding effectiveness is improved by using the absorbing material and new shielding box.The absorbing material is fixed on the surface of shielding box,which can reduce the ECEI system ambient noise level.The shielding optimization improves the signal to noise ratio and the ECEI can work normally even the LHCD injection power is higher than 2 megawatts.Besides the optimization of shielding,we also design the remote control system for ECEI.The remote control system includes three parts,RF attenuator remote control system,the control software design of microwave oscillator and the remote control of ECEI system's power supply.The main part of remote control system is the attenuator remote control system,which insures the availability of ECEI system output signal.The remote regulation system of attenuator uses the Arduino single chip microcomputer incept the control signal from computer software and output the serial signal to the conversion circuits,which transform the serial signal to parallel signal.Because the attenuator's power supply voltage and control voltage is 0 or-5 and the parallel signal is +5 or 0,the parallel signal need to be converted.The circuits use the zener diodes and the 74HC04 chips realize the voltage convert.The attenuator remote regulation system help the ECEI system acquire more valid data on EAST and the remote control system is more effective than manual control.At last this paper introduce a kind of RF spectrometer.This diagnostic can detect the level and distribution of radio frequency radiation in the surrounding of plasma device,which is caused by the magnetic reconnection or other physical process.