研制了数字低电平系统(DLLRF)替换了合肥光源(HLS)原模拟系统,实现储存环高频腔的频率调谐和高频加速场的快速幅相反馈控制。该系统主要由模拟信号变频和基于FPGA的数字处理两大功能模块构成。经过离线和在线调试,DLLRF闭环控制下高频场的无载幅相稳定度达到±0.1%和±0.1°。带束流运行后进一步优化了环路参数,储存环最高流强达到460 m A,并成功实现了300 m A TOP-OFF运行模式,高频场的载束幅相稳定度达到±0.2%和±0.2°。
3 sets of 500 MHz 300kW RF amplifiers to be used at the main ring of the Shanghai Synchrotron Radiation Facility (SSRF) have been installed on site.The Site Acceptance Test (SAT) of the first RF power source was completed in last March.The second and third RF power sources are going well and will be finished in October.The type choice, the layout of the RF power sources and the comparison between the SAT conclusion and the design goals are presented.
主信号源是高频数字化低电平控制系统(Low Level Radio Frequency,LLRF)的重要组成部分,它不仅用于产生高稳定度的参考信号,还用于产生控制系统所需的高精度工作时钟,其性能是高频系统性能的重要保障。本文以上海同步辐射光源(Shanghai Synchrotron Radiation Facility,SSRF)的主信号源作为研究对象,通过采用锁相环技术和直接模拟合成技术实现了500 MHz的单频信号源。实验测试结果显示:两种技术分别实现了-125 dBc/Hz@1 kHz和-132 d Bc/Hz@1 k Hz的相位噪声,均满足上海光源高频系统对信号源的性能要求。
