Design Of Sweep Generator Based On DDS Technology

Sweep generator is an instrument for measuring transmission characteristics of the network. In this paper, the working principle of sweep generator were analysed emphatically, then a design scheme based on DDS technology were put forward. After analysing the research status of the sweep generators in the market and the system characteristics, we make sure the performance index and general scheme. In this design, the sweep generator consists of five parts, they respectively are swept signal generator circuit, gain control circuit, magnitude and phase detecting circuit, control and processing unit and human-machine interface circuit. In which swept signal generator adopt the pure digital technique which has high-speed frequency conversion time, extremely high frequency resolution, lower phase noise and the outstanding advantage of programe control, superadd the gain control circuit and the magnitude and phase detecting circuit, the sweep generator can adapt to various test requirements. Embedded microprocessor C8051F020 were used as the control and processing and the compositive magnitude and phase detecting circuit and true color LCD make the design of sweep generator more simple, the debugging more convenient and the performance more stable and reliable. In addition, this sweep generator can make stepping measurement automatically in the whole frequency range. We can preset measuring range and stepping frequency, so the detailed frequency characteristic curves can be seen clearly. This function brings users much convenience.