Dds Arbitrary Waveform Generator Design

The DDS(Direct Digital Frequency Synthesis) technique adopts full-digital synthesis methods. The generated signals have advantages of high frequency resolutions, fast frequency switching, continuous phase while frequency switching, low noise phase and being able to generate arbitrary waveforms.The thesis analyses the principle of DDS and the performance of output signals. Sine and square waveforms are generated with AD9851. An arbitrary waveforms generator which can generate the triangle waveform, sawtooth waveform, FM, PM, AM, burst waveform and other waveforms is designed with FPGA. Arbitrary waveforms can be downloaded to the arbitrary waveforms generator via serial port of PC. The structure that combines a phase accumulator with frequency word calculation unit is used to design the frequency modulation circuit. This structure can not only realize broad band linear frequency modulation, but also nonlinear frequency modulation. The design and debugging of the hardware and the software are finished. The test results for the prototype machine show that the specifications have meet the design requirements.