【作者】 高沈；

【导师】 刘洛琨；

【作者基本信息】 解放军信息工程大学 ， 军事通信学， 2009， 硕士

【摘要】 目前国内外关于超宽带的研究主要集中于短距离、高速率应用,对中远距离应用较少涉及。基于中远距离超宽带的无线传输技术可以进一步拓展超宽带的应用范围,使其应用形式更加灵活、体系结构更加完整。特别是其固有的抗干扰及传输隐蔽能力强的技术优势,可以在公安、消防、救灾等多种特殊领域场合得到重要的应用。多种超宽带通信体制中,Chirp-UWB体制应用于中远距离通信有其独特优势。然而目前实用的Chirp-UWB技术主要定位于短距离、低速率、低成本应用。所以研究适用于中远距离的Chirp-UWB系统实现结构及与之相关的关键技术十分有意义。本文的主要研究工作如下：第一,Chirp-UWB信号产生技术。分别研究了基于模拟VCO及其非线性校正、直接数字合成(DDS)、DDS+锁相环、DDS+变频+倍频四种信号产生方案,详细分析了各自的性能及应用于Chirp-UWB通信系统的可行性。研究表明,基于DDS+倍频+变频的信号产生方案结合了模拟和数字信号产生技术的优点,是一种较好的大带宽Chirp-UWB信号产生方案。第二,Chirp-UWB信号采集处理技术。首先研究了利用高速ADC对Chirp-UWB信号进行采样并高速数字处理的实现方案,然后给出一种有源频谱压缩结合低速ADC采样的实现方案。后一方案利用时域相乘实现频域相关,从而将极大带宽的Chirp信号压缩为一个窄带信号,避免了高速采样及高速数字信号处理,是一种有效的Chirp-UWB信号采集处理方案。第三,Chirp-UWB系统硬件实现非理想因素分析。针对一种实用的Chirp-UWB实现结构,从工程实现角度分析了非理想因素的来源,通过建立数学模型,研究了其对系统性能的影响,并给出消除或降低这些影响因素的解决办法和思路。最后,基于以上研究,选择DDS+变频+倍频的信号产生方案及有源频谱压缩的接收结构,设计了Chirp-UWB系统基带及射频收发电路。更多还原

【Abstract】 At present, both at home and abroad, the researches of Ultra-Wideband (UWB) focus on short-distance and high-speed application, scarcely touching upon medium or long distance applications. The wireless transmission technology based on the medium or long-distance UWB will further expanding the scope of UWB application, making its application form more flexible and its architecture more integrated. In particular, the strong technological superiority of anti-interference and capacity of covert communication make it very useful in the application of military, public security, fire safety, rescue and many other special occasions.Several of UWB system, the Chirp-UWB has unique advantage in the applications for medium or long-distance. But the current practical technique of Chirp-UWB is mostly used in the application of short-distance, low-speed and low-cost. So it is very useful to study the implement structure and the Key Technique of Chirp-UWB applications for medium or long distance.The main research contents include:Firstly, the techniques of Chirp-UWB signal generation. This thesis, studies on four signal generator programs:using analog VCO and its nonlinear correction technology, direct digital synthesis (DDS), DDS+PLL, DDS+mixer+frequency multiplier respectively, and gives detailed analysis of the performance of four programs used in the Chirp-UWB communication system. The results show that, DDS+mixer+frequency multiplier is a better Chirp-UWB signal generator programs that can generate a large bandwidth signal which combining analog signal processing technology and digital signal processing technology.Secondly, the techniques of Chirp-UWB signal sampling and processing. In this thesis, a program based on architecture of software radio is firstly studied, in which the signal is directly sampled by a high-speed ADC and then implements the digital signal processing program. Then, a program based on active spectrum compression and low-speed ADC sampling is given, which uses the character of signal that the time-domain multiply equals to frequency-domain correlative. This approach puts the extremely wideband Chirp-UWB signal compressed to a narrow-band signal in frequency domain, so as to avoid high-speed sampling and high-speed digital signal processing.Thirdly, the non-ideal factors of the Chirp-UWB system hardware design analyzed. Aim at a practical implementation structure of the Chirp-UWB, the thesis gives an analysis of the source of all non-ideal factors and their influence on system performance by setting up the mathematical model, and then gives the solutions or ideas to reduce or eliminate the impact of these factors.Finally, the thesis chooses the program of DDS+mixer+frequency multiplier to generate signal and the receive structure based on active spectrum compression and low-speed ADC sampling, designs the base band and RF circuit of Chirp-UWB receive and transmit system.更多还原