Design and realization of digital low level RF system for SSRF

Based on digital technology, using the up and down converter, IQ modulator and demodulator techniques, the magnitude control, frequency control and feedback phase control are realized and the low level RF system for Shanghai synchrotion radiation facility(SSRF) is designed. The beam current of SSRF is about 300 mA.In order to suppress the Robinson instability and the zero-mode beam instability, the RF feedback and zero-mode beam feedback will be added. How to design the up and down converter,IQ modulator and demodulator, clock distribution and phase locked techniques will be discussed in this paper. The results of the system testing at high power are given in this paper. The low level RF system has realized the design requirements: amplitude control accuracy rate of ± 1%, frequency contro