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A Study On The System Of Digital Pulse Compression For Multi-waveforms In Frequency Domain

Posted on:2002-09-29Degree:DoctorType:Dissertation
Country:ChinaCandidate:J H WuFull Text:PDF
GTID:1118360032453771Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
Pulse compression technique is widely used in modem radar systems. Large timeband product signals such as linear frequency modulation signals (LFM), nolinear frequency modulation signals (NLFM), phase coded signals and so on are used in pulse compression technique to improve the resolution in range domain. Pulse compression technique includes two key techniques: the pulse compression signal generation and processing. With the progress of science and technology, pulse compression processing systems are developed to all-digital systems from analogue or digital-analogue ones. Digital pulse compression processing can be divided into pulse compression processing in time domain and pulse compression processing in frequency domain. This dissertation mainly studies the digital pulse compression processing technique in frequency domain, which possesses the remarkable advantages in digital pulse compression processing. Pulse compression performances of many pulse compression signals are analyzed in frequency domain. And the methods to design kinds of range sidelobe suppression filters (5SF) are proposed. Based on the theoretic analysis and computer simulations, a multi- waveform pulse compression system in frequency domain is successfUlly exploited, which is applicable to complete pulse compression processing of linear frequency modulation, nonlinear frequency modulation waveforms and phase coded signals. The designed bandwidth of signals reaches 5MHz and pulse compression ratios are under 256. The experimental results demonstrate that the specification characteristics meet the requirements of practical radar systems. And the results are satisfactory. The main content and creative work in this dissertation include: (1) The characteristics of various pulse compression signals with 95 -?~25O pulse compression ratios is comprehensively investigated in frequency domain. (2) The effect of the sampling rate on RMS, the crucial performance of the pulse compression, is analyzed. The signal design and processing are based on the practical Nyquist sampling frequency and the results of the computer simulations conform to that of the system experiments. (3) A group of large time-bandwidth product NLFM signals are synthesized with various window-functions in frequency domain and the analogous application of some window- functions have not been reported before. Meanwhile, the computer simulation results of the signal resolution and Doppler response are also discussed and compared with the actual experimental results. At last, the selection principles of window function for large time- ?-. bandwidth product NLFM signals are proposed. These signals can be used in long-range radars and will increase the dynamic range of target detection. (4) The sidelobe suppression filters (SSF) for biphase coded signals have been researched for long time. But the research on long-code signal processing in frequency domain has not been reported before. This dissertation studies the range SSF techniques for long-biphase coded signals by applying digital processing in fi~quency domain. By analyzing the spectrum characteristics, a SSF design method in frequency domain which is suited for various code lengths is presented. (5) J. W Taylor and etc. have presented a class of quadriphase coded signal with good properties, and described the characteristic of 13-28-bits signals. The dissertation gives the details of longer quadriphase coded sig...
Keywords/Search Tags:Radar, Pulse Compression, FFI Linear Frequency Modulation, Nonlinear Frequency Modulation, Phase Code, Sidelobe Suppression
PDF Full Text Request
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