In a modern battle, a ground-based radar jammer is asked to transmit many kinds of jamming or decoy signals to protect a military facility. The author of this article puts forward an issue to produce various signals controlled by software. This system takes a FPGA chip as a core to be on-line programmable and applies PC/104 host to realize a miniaturized system. In addition, the application of DDWS and high-speed digital-to-analog control technology is added to implement a broadband signal's generation. In practice, this system is applied into a kind of radar system and is validated its performance satisfies the requirements of this project.