Research Of Mini Wideband Multiple Channels Synchronous LFM Signal Generation Technology

High-performance broadband signal source has become a key component of modern radar system.This paper aims to realize a multi-channel strict synchronized wideband LFM signal generation.And at the same time,it has the features of miniaturization,low power consumption and low cost.So it is suitable for small digital array radar applications.According to the application requirements of the radar system,the overall technical scheme of the signal source is designed.There are two method to achieve this design,DDFS technology and DDWS technology.On the basis of those advantages and disadvantages,this paper chooses DDFS as its signal generation method.This article describes the multi-channel synchronization principle of DDS chip AD9914,especially the multi-chip output synchronization requirements of AD9914.Synchronous system clock,SYNC_OUT synchronization signal and synchronous I / O_UPDATE signal are the requirement.Hardware implementation of the circuit is designed,includes electrical structure,the main selection,the clock circuit,power supply circuit,etc.The system clock frequency of the core chip AD9914 is up to 3.5GHz,and its output signal frequency is up to 1.4GHz,which meets the system requirement for the DDS signal.At last,the output signal is tested,including the system clock signal provided by ADF4355-3,single tone output and LFM output signal of AD9914.The results of the analysis show that the output signal has a flat band in the frequency band and good performance after pulse compression processing.In addition,the signal generation system has the characteristics of low power consumption,small volume and low cost.