Development Of FPGF-based Tune Measurement System At HLS ?

Tune is an important parameter in storage ring.Domestic and foreign large accelerator have tune measurement system.The tune is the number of transverse beta oscillations after the charged particles run one revolution in the storage ring.Since the amplitude of transverse beta oscillations is small,the additional excitation signal is needed.Sweep frequency excitation signal and narrow band white noise excitation signal is often used.Each have advantages and disadvantages of different excitation signal type,Hefei light source of the existing tune measurement system is based on the spectrum of the sweep excitation measurement.In order to meet the different research conditions of the machine,we need to design a new tune measurement system.This paper fully investigates many tune measurement systems,and introduces the measurement principle of the tune and the corresponding digital signal processing principle.On the basis of synthesizing various experimental schemes and understanding the relevant theories,the tune measurement system composed of front end electronics,FPGA,ARM and host computer is proposed.The function and implementation method of the system architecture and each module are introduced in detail.The FPGA function module mainly includes signal excitation,signal acquisition and communication module.The signal excitation module includes parameterized swept excitation signal and white noise excitation signal.The signal acquisition part mainly controls the ADC through FPGA and passes the digital signal collected by ADC Filtering,decimation etc.The main function of ARM is to carry on the Fast Fourier transform to the digital signal and find the peak of the amplitude after the transformation,the second is to play the role of a bridge,the upper computer GUI program through the ARM internal state registers can read and write operation.FPGA and ARM data transmission through the AX 14 bus protocol,ARM and the host computer data transmission through socket programming.The experimental results show that the statistical resolution of horiontal and vertical direction is 0.0006/0.0001 based on sweep excitation mode,and the statistical resolution of horizontal and vertical directions is 0.0007/0.0036 based on bandwidth white noise excitation mode respectively.The system is compact,low cost,rich in function,can be programmed online to meet different machine research.