Design And Implementation Of Radar Signal Generator And Jamming Signal Generator Based On Ddws

High-powered radar system and jamming system were dire needed in Modern hign-tech war. Radar signals with large instantaneous bandwidth are widely used for its high distance resolution, strong anti-jamming and reliability of detection and recognization. Accordingly, the signals with different bandwith, complicated shape, multiplicated modulation techniques are acquired by digital jamming. Above all, the signal generator with high performance is significant for both radar system and jamming system.Direct Digital Waveform Synthesis technology is widely used along with the development of massive and high speed memory array, super high speed DAC and high-powered FPGA. DDWS provides precise signal phase and powerful frequency resolving capability, meanwhile produces sorts of complex waves in a more convenient way and can improve the spectum of signal.The signal generator based on DDWS technic is designed. The signal generator can produce a in-phase channel and a quadrature channel baseband signals of which maximal bandwidth is 240MHz and time-width is 200ms. Based on the above context, the following contents are studied in this article.1. The Generation of wide bandwidth signal.Firstly, the theory of radar signal is introduced. Secondly, the performance of LFM and V-FM signals is analyzed. A method of anti-jamming for V-FM signal is proposed.Thirdly, the module of broad-band noise is analyzed.Finally, the principle and excellences of DDWS technic are introduced. The DDWS is the technical foundation of the signal generator.2. Design of the radar/jamming signal generator. Firstly, a portable signal generator system was studied. The performance of the signal generator is introduced. Then the design of massive and high speed memory array, high speed DAC, clock distribution and CPCI interface is discussed in detail. The massive and high speed memory array is used for storing data from PC. The massive and high speed memory array also transforms the data from memory to DAC in high speed under the control of FPGA. The high speed DAC is used for transforming data into wide-band signal. The module of clock distribution can produce high speed, stable and coherent clock for different components. The CPCI interface is used for communicating with other CPCI boards.3. Error analysis of system and pre-distortion calibration technique.Firstly, the sources of system error are analyszed. The mathmetic model of amplitude and phase error is researched. The influence of error on LFM signal pulse compression is discussed. According to the error model, the pre-distortion calibration method for system error and the inconsonance between the I channel and the Q channel is researched at last.