Abstract: In order to solve problems of low precision and small frequency range of analog signal sources and unability to satisfy system requirement of bespoke direct digital frequency synthesis signal sources on aspects of control mode and frequency setting, a signal source based on FPGA was designed. The source is based on direct digital frequency synthesis principle, it adopts modularization design of FPGA and can output sine wave, square wave and triangular wave with adjustable frequency, phase and amplitude. The experimental results show that the signal has perfect quality of output wave, high frequency resolution and convenient control.