Phase characteristics of solid-state amplifiers in sub-harmonic bunchers

To study the phase characteristics of solid-state amplifiers (20 kW/142.8 MHz, 10 kW/571.2 MHz) in sub-harmonic bunchers(SHBs) of the BEPC Ⅱ linear accelerator, phase shift in pulse and phase stability are measured using a digital measurement method based on field programmable gate array(FPGA ). The hardware of the measurement system includes the frequency synthesizer, digital signal processing board(FPGA) and PC, and the software includes an internal algorithm on FPGA, communication procedures and PC client interface procedures. The measurement results of phase characteristics are consistent with the actual situation, which is the basis for the further implement of phase compensation in SHBs.