Research And Design Of SFCW Signal Source

The step frequency signal as a special signal source,which has been widely used in many fields because of its unique characteristics.This subject is aimed at the synthesis method of step frequency continuous wave and combined with the system can be used for wall-penetrating radar.In-depth research on the step frequency source from the aspects of signal analysis,key indicators,program selection and performance testing etc.And on this basis,design the whole step frequency continuous wave transceiver system which can be applied to the design of wall-penetrating radar.This article takes step frequency continuous wave frequency source as the main body and mainly completes the following works:1.This article analyzes the advantages and disadvantages of various frequency sources and their application.Finally,I select the step frequency continuous wave signal as the research focus.At the same time,design a step frequency continuous wave transceiver system that can be applied to wall-penetrating radar.2.According to principle of various frequency synthesis technology,I determined the step frequency synthesis scheme: DDS + PLL.And base on ADI's AD9850 and ADF4350 design step frequency source.At the same time,I design a transmitter compensation circuit.Finally,I design and test the PCB board.3.This article selects the appropriate receiver solution according to the system requirements and popular receiving solutions currently.And base on ADI's AD8347 design a Zero-IF receiving system.Finally,I design and test the PCB board.After testing,the research and design of the SFCW signal source of this subject completes the indicators of the transmitted signal as: the frequency range is 1.1GHz-2.1GHz,step frequency is 500 k Hz,the transmit power is about 10 d Bm,the phase noise is less than-90 d Bc @ 100 k Hz,the spur is better than-40 d B,and frequency conversion time is 116 us.The S11 of the Zero-IF receiver in the 1.1GHz-2.1GHz band is less than-3d B.Realize the fast frequency conversion in the case of broadband.It meets the design requirements and has certain practical value.