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摘要MIMO技术能够把无线移动信道中的散射路径等同于多个相互独立的并行传输信道，用来传送信息，能在不增加额外带宽和天线发射功率的情况下，有效增加传输速率，从而提高频谱利用率。将MIMO技术应用于雷达探测领域，以此来提高雷达系统的整体性能是一种全新的尝试和探索。当MIMO雷达的概念被提出来以后，MIMO雷达凭借其自己拥有的诸多优点以及超越其他雷达的无法比拟的特性，吸引着国内外众多专家学者的眼球，飞速成为国内外的研究热点。27049
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本文设计的调制器是应用于4×4天线的MIMO雷达系统中，因此选用了QPSK雷达调制器。作为设计的调制器，四相相移键控的调制方式满足4相输入输出的条件。由于在空间中的同一个频带中，传输的信息是四个相位的信息量，因此其具有频谱利用率高、传输速率快的优点。而正交传输又使得QPSK调制器具有抗干扰性能强、频谱特性好等优点，因此更加符合MIMO雷达的特性。
本文采用的调相法，利用串并转换单元将二进制代码信息每两个一组按照时钟频率依次输出，然后通过逻辑选相电路从载波发生器输出的5GHz的载波里按照我们编写的规则，以“00”选择输出45°相位载波、“01”输出135°相位载波、“10”输出225°相位载波、”11”输出315°相位载波选择输出，这样连续输出的信号就构成了调制信号。在此原理基础上，利用Maltlab以及QuartusII完成各个模块的设计，并针对其进行仿真。
关键词 MIMO雷达，数字通信，调相，QPSK调制器，载波频率
毕业论文设计外文摘要
Abstract
MIMO technology can make scattering path of the wireless mobile channel into multiple independent parallel transmission channel which used to transmit information. We can use it to improve transmission rate and frequency spectrum efficiency without improving extra bandwidth and antenna power. Bring MIMO technology into the radar is an exploration of research for a new type of radar system. After putting forward the concept of the MIMO radar, with so many advantages MIMO radar attracts many scholars to study and explore, and then becomes the hot researching spot.
The MIMO radar system modulator which need to be designed is applied to 4 x 4 antenna, so a QPSK radar modulator is chosen. In the designed modulator, the QPSK fulfills 4 inputs and 4 outputs, because at the same band in space, the transmitted information have four phases , therefore it has high spectrum utilization rate and fast transmission speed. Also, the orthogonal transmission makes QPSK modulator has the advantages of strong anti-interference performance and good spectral characteristics, so QPSK modulation in mobile communications and satellite communications are applied widely, in line with the characteristics of MIMO radar.
With the use of deserializer, the introduced phase-modulation method in this paper will change a set of binary code into two by two, then outputs in the frequency of the clock sequentially. the logical selection phase circuit will choose 5GHz carrier in accordance with the rules that "00" select the output of 45 DEG phase carrier, "01" output 135 DEG phase generated carrier, "10" output 225 DEG phase generated carrier, "11" output 315 DEG phase carrier selection output from the carrier generator output. this continuous output signal constitutes the modulated signal. on this basis, each module has been designed and put it into simulation separately.
Key word：MIMO radar, Digital communication, phase，QPSK modulator, carrier frequency
目 录
1 绪论 1
1.1 研究背景 1
1.1.1 MIMO雷达简介 1
1.1.2 QPSK调制简介 2
1.1.3 QPSK调制原理 3