The three bump magnets in the booster extraction system of SSRF are driven by a signal generator with an external trigger.The signal generator must have three independent and controllable outputs

and both amplitude and make-and-break should be controllable

with current state information being readable.In this paper

we describe a signal generator based on FPGA and DAC boards.It makes use of characteristics of both FPGA flex programmable and rich reconfigurable IO resources.The system has a 16-bit DAC with four outputs

using Matlab to write a GUI based on RS232 protocol for control.It was simulated in Modelsim and tested on board.The results indicate that the system is well designed and all the requirements are met.The arbitrary waveform is writable

and the pulse width and period can be controlled.