Study And Design Of Harmonic Signal Generator Based On FPGA/DDS

With the development of frequency synthesis theory and high speed LSI (Large Scale Integration), the signal generator, a sort of electronic equipment, has been widely applied in many fields such as communication, detection and navigation. Specially, in the field of high voltage power system, the standard signal source, which simulates the harmonic of electric power lines, is needed to calibrate the performance of detecting instruments, such as the detection of phase of high voltage electric power lines, the measurement of performance of lightning arresters, the calibration of ammeters, and so on. Therefore, the paper designs a new parameter-adjustable harmonic signal generator, and the subject has been sponsored by the technological fund of Changzhou city.Firstly, the development of frequency synthesis technology is introduced. The direct digital frequency synthesis technology and the traditional frequency synthesis technology are compared. Secondly, the principle and configuration of the DDS are studied. The output spectrum of the DDS on the presence of both ideal parameters and actual parameters is analyzed. Based on analyzing the output spectrum of the DDS, three main factors causing output spurs are analyzed in details and the simulation study of some methods to reduce spurs is presented. In the end, a parameter-adjustable harmonic signal generator including hardware and software is developed.In the course of designing the system, this paper, using MAX+PLUSâ…¡ and VHDL, designs a frequency, phase, amplitude and harmonic proportion-adjustable harmonic signal generator on the basis of Altera FPGA chip EPF10K70RC240-2. The system configuration of the signal generator is presented in details and the whole system including software and hardware is developed. Testing results demonstrate that the system performance attains the demands. The harmonic signal generator has many advantages such as easy-use, high integration, and so on.