Large Bandwidth Linear Fm Signal Generation Method And System Technology Research

Waveform design and generation is one of the key techniques in UWB-SAR development. With an air-borne UWB-SAR system as the background, the foundational theory of LFM signal, the systemic error model and the design and implementation of LFM generator were discussed in this paper. The paper is composed of four parts: First, the foundational theory of LFM (Linear Frequency Modulated) signal was studied. Based on the theory of radar, the essentiality of LFM signal was discussed. Meanwhile some methods that generate LFM in digital or analog were provided in this part. Second, this dissertation focuses on the error analysis of digital method of the pulse compression signal generation based on LFM signals. The difference and similarity between technique of the direct reading of the stored digital waveform and technique of the direct digital synthesis were also compared. Except, the error model of orthogonal modulation and double frequency technology were studied. Third, the design and implementation of ultra wide band LFM generator were studied. An ultra wide band LFM pulse compression signal generator with 400MHz carrier and 300MHz absolute bandwidth was developed successful. Its repeated frequency was 1kHz with 20us width of pulse. Fourth, the generator was tested and evaluated. The author provided the testing measure and result.The production of this dissertation was successfully applied to the air-borne UWB SAR system, and proved to be feasible and efficient.