基于FPGA的信道化接收机信号处理技术

发布时间：2018-04-30 07:06

本文选题：多级信道化 + 信号跨信道　；参考：《西安电子科技大学》2014年硕士论文

【摘要】：现代战场环境中电磁信号形式纷繁复杂、瞬息万变,呈现出高密度、多频段和大带宽的特点,要求电子侦察接收机有更好的性能。数字信道化接收机具有很大的发展潜力,但目前其性能还是受到ADC采样速率与量化位数的限制,不能同时满足大动态范围和大瞬时带宽的要求。信号跨信道问题是信道化接收机必然存在的问题,信道判决和消除虚假输出技术是信道化接收中的重要环节。用瞬时测频法消除虚假信号时,由于利用相位法测量频率,对信号的信噪比要求很高,且当单个信道内有同时到达信号时,不能准确测量出信号的频率,无法进行信道判决。本文针对信道粗略划分时的信号跨信道问题,研究了一种有效的信道判决方法,先利用信道化瞬时测频法测量各个信道内信号的频率,再进行信道判决,具有同时到达信号的处理能力。同时,还研究了一种基于FFT的信道化瞬时测频方法:全相位FFT-相位推算法,该方法先对信号进行全相位处理,然后利用FFT实现数字信道化,准确测量出各个信道内的信号,能够利用较少的信道划分,得到较高的测频精度,且具有多信号处理能力。本文还研究了加窗DFT对频率测量的影响,讨论了不同窗函数适用的场合:如果单频信号或多个频率成分之间幅度差距不大,应选用矩形窗函数,DFT分辨率高且主谱线幅度大,易于分离信号和检测;如果信号中有多个频率成分且幅度差距较大,则选择旁瓣电平小的窗函数,防止小信号被大信号的旁瓣淹没。最后,用FPGA实现了信道化瞬时测频和信道判决算法,表明算法的有效性和实用性,具有一定的工程应用价值。
[Abstract]:In the modern battlefield environment, the electromagnetic signal forms are complex and rapidly changing, showing the characteristics of high density, multi-band and large bandwidth, which require better performance of electronic reconnaissance receiver. Digital channelized receiver has great development potential, but its performance is still limited by ADC sampling rate and quantization bit number, which can not meet the requirements of large dynamic range and large instantaneous bandwidth at the same time. Signal cross-channel problem is an inevitable problem in channelized receiver. Channel decision and elimination of false output are important links in channelized receiver. When the false signal is eliminated by the instantaneous frequency measurement method, the signal to noise ratio (SNR) of the signal is very high because of the frequency measurement by the phase method, and the frequency of the signal cannot be accurately measured and the channel decision can not be carried out when the signal arrives at the same time in a single channel. In this paper, an effective channel decision method is studied to solve the cross-channel problem when the channel is roughly partitioned. Firstly, the frequency of the signal in each channel is measured by using the channelized instantaneous frequency measurement method, and then the channel decision is carried out. Has the processing ability to simultaneously arrive the signal. At the same time, a channelized instantaneous frequency measurement method based on FFT is also studied. The method firstly processes the signal in all phase, then uses FFT to realize digital channelization, and measures the signal in each channel accurately. It can make use of less channel division to obtain higher frequency measurement accuracy and has multi-signal processing ability. This paper also studies the effect of windowed DFT on frequency measurement, and discusses the applications of different window functions: if the amplitude difference between single frequency signal or multiple frequency components is not large, the rectangular window function should be chosen with high resolution and large amplitude of main spectral line. If the signal has multiple frequency components and the amplitude difference is large, the window function with small sidelobe level is selected to prevent the small signal from being submerged by the sidelobe of large signal. Finally, the channelized instantaneous frequency measurement and channel decision algorithm are realized with FPGA, which shows that the algorithm is effective and practical, and has certain engineering application value.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN851

【参考文献】