Multi-function Signal Generator Based On Dds Technology Research

Dierct Digital frequency Synthesis(DDS) was a dvanced rapidly in early 1970s and has been developing owing to its entirely digital structure. The appearance of Field Programmable Gates Array has changed the design method of digital electronical system and provided a new design model. With the two technologies and the flexible control ability of MCU, Functional Waveform Generator, has been developed. This new signal source can generate high frequency waveform data and also can change parameters of the Functional Waveform Generator.This paperwilld escribeit sp rocessa ndc haracteristics.Firstly, the fundamental principle and output spectrum properties of DDS is analyzed, and the spurious distributing rules are given. A deep study of the spectrum characteristics of spurs brought by phase truncation is discussed in particular, and then simulations are performed to validate the results using Matlab. Based on the spectrum analysis of DDS, this paper introduces some methods of Spur Reduction.Secondly, the desired waveforms are synthesized by DDS technology. The realization of DDS depends on high speed and high performance digital devices, so the combination of FPGA device and DDS technology is adopted in this paper. The design scheme of FPGA device is described in detail, and this thesis deals with the optimization design of the key technology. Consequently the digital circuits of this system are accomplished. In addition, the peripheral hardware circuits such as amplitude controller, digital-to-analog converter and low-pass filters are designed for obtaining the analog signals.Finally, some experiments are performed to test the functions of waveform generator. The results of these tests show that the scheme presented meets the anticipative performance requirement.