Design And Implementation On The Double Channel Broadband Waveform Generator

With the development of digital circuits and software radios,in the modern radar electronic warfare,the broadband radar signal has attracted the attention of all counties because of its good target detection and recognition ability and anti-all kinds of active passive interference.Not only that,but also in the electronic warfare broadband radar can produce quick parameter changing and arbitrary waveform output signal.In some cases,it is also required to have the ability to output several different signals in a multi-channel.At the same time,DDS,as a key technology to produce the radar waveform,has been widely used.Programmable digital waveform generator has the advantages of high stability,adjustable parameters,a variety of waveform output capabilities.Therefore,the study of broadband dual-channel waveform generation module has a very important significance.After deep research and analysis of two different DDS working principle and error model and three methods to generate IF signals,this thesis puts forward the waveform design based on direct digital waveform synthesis technology,using digital baseband + digital orthogonal modulation.In this thesis,not only multi-channel parallel structure based on the multi-phase filter and multi-phase NCO is used in the FPGA to reduce the sampling rate,but also NIOS ? which is an on-chip system provided by Altera controls the waveform parameters to increase the flexibility of the system.Finally,the design used for simulation,including delay and synchronization,different bandwidth,different center frequencies and different signal forms,and the test results in full compliance with the design indicators,shows that the design module achieves a broadband dual-channel waveform output.The main work of this thesis is divided into the following points:1?Introduce some basic theories of radar signal processing,and analyze the working principle and error model of DDS and the generation method of IF LFM.2?The structure of polyphase filter and NCO is studied.On this basis,the feasibility of multi-channel parallel structure instead of interpolation is verified.3?Introduce NIOS ? processor core,and researching and analyzing the use of NIOS ? technology for soft core design and development process.4?Put forward the basic frame structure of broadband double channel waveform,and complete the choice of the device,the design of the program and the feasibility of the program validation analysis.5?The hardware and software modules are simulated,as well as testing the entire system,including synchronization,bandwidth,center frequency and signal form,and technical indexes are also analyzed.