The Design Of Linear Frequency Modulation Radar Waveform Generator Based On DDS Technology

With the development of modern digital technology and the Very Large ScaleIntegration electrocircuit(VLSI), the method of digital waveform synthesis is widelyused in radar systems now. The waveform generation using digital system is of strictcoherence, repetitiveness, high stability and programmable capability, which can alsoeasily realize the waveform parameter's agility and generate arbitrary complicatedwaveforms in order to meet the urgent requirement for anti-interference and strongsurvival ability of radars under modern electronic warfare environments. The DirectDigital Synthesis (DDS) technology is widely used in civil and military affairs.The thesis briefly introduces fundamental Radar operational principle and LFMsignal theory firstly, setting out the merit of DDS, then analyzing the principle andperformance of DDS method. According to project request, combining the FieldProgrammable Gate Array (FPGA) and DDS technologies, implementing a waveformgenerator of LFM radar system. At the end of the paper, waveform of output areshown and analyzed. The test results completely meet the system requirements.The primary work in this dissertation:1. Analyzed the principle and distribution rule of spurious in DDS and somemethods to reduce the spurious;2. According to project function request and interface request, accomplished thedesign of the waveform generator implement scheme;3. Accomplished the VHDL programming and simulation of FPGA control module;4. Based on FPGA and DDS technology, accomplished designing of principle circuitand PCB of the waveform generator, and debug the PCB;5. Measured fully and analyzed effectively LFM Pulse signal and accomplished thedebug with the signal generator. The compression performance of LFM pulse isanalyzed. Secondly, the influence of phase error, amplitude error and IQ modulation and demodulation errors is studied.