Abstract
Signal generator is very important in modern electronic instruments. In the experiments，product development and debugging and system testing is essential，and the traditional signal generator performance is very limited，can not meet the requirements of some users. Direct Digital Synthesis is the new generation of frequency synthesis technology，it uses the numerical control signal the phase increase technology，has the frequency resolution high，the frequency cuts quickly，when frequency cut the phase continuously low as well as the entire digitization is easy with the phase noise to integrate and so on the merit is widely used. In recent years the super velocity digital circuit development as well as to the DDS thorough research，the DDS highest operating frequency as well as the noise performance approached and achieves the phase-lock frequency synthesizer suitable level. Along with this kind of frequency synthesis technology development，already widely applied to the communication，the navigation，the radar，remote control telemetering，electronic countermeasure as well as modernized do main and so on instrument measuring appliance industry.
The thesis analyses the principle of DDS and the performance of output signals. An arbitrary waveforms generator which can generate the triangle waveform, saw tooth 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 hardware and the software are finished.
Key words： Verilog HDL；Arbitrary waveforms generator；Direct Digital Frequency Synthesis；
