  Shanghai Synchrotron Radiation Facility (SSRF) is a 3.5 GeV storage ring with
a bunch rate of 499.654 MHz, harmonic number of 720, and circumference of 432
meters. SSRF injection works at 3.5 GeV, where the multi-bunch instabilities
limit the maximum stored current. In order to suppress multi-bunch
instabilities caused by transverse impedance, a bunch-by-bunch transverse
feedback system is indispensable for SSRF. The key component of that system is
the bunch-by-bunch transverse feedback electronics. An important task in the
electronics is precise time synchronization. In this paper, a novel clock
synchronization and precise delay adjustment method based on the PLLs and delay
lines are proposed. Test results indicate that the ENOB (Effective Number Of
Bits) of the analog-to-digital conversion circuit is better than 9 bits in the
input signal frequency range from 100 kHz to 700 MHz, and the closed loop
attenuation at the critical frequency points is better than 40 dB. The initial
commissioning tests with the beam in SSRF are also conducted, and the results
are consistent with the expectations.
