The Design Of Front-end Of Radar Signal Resource Based On DDS

Direct Digital Frequency Synthesis (DDS) technology has always been the hotspot of study on frequency synthesis technology, since it was introduced in 1971 firstly. With the rapid development of digital integrated circuit and micro-electronics, DDS has been widely applied in many fields, such as communication, navigation and radar etc.In this paper, the basic theory of radar signal, as well as the fundamentals and features of Direct Digital Frequency Synthesis (DDS) and Phase locked loop (PLL) are described in detail. At the same time, the design and realization of signal generator based on DDS are emphasized in this paper. In order to makes full use of the advantages of DDS and PLL, a project based on DDS+PLL is adopted in the radar signal resource. The realization of the project is mainly composed of two parts. The first part is low frequency signal generator based on DDS, and the second part is high frequency signal synthesizer. The author completes the whole design flow of the signal generator based on DDS, including project design, hardware circuit design and VHDL programming. The generation of low frequency signal based on DDS is completed by means of FPGA configuring DDS chip.Many different signals, such as single tone signal, Linear Frequency Modulation (LFM) signal and Stepped-frequency Pulse (SFP) signal etc., can agilely generated by this signal generator for some requirements.