本文選題：多級信道化 + 信號跨信道　； 參考：《西安電子科技大學(xué)》2014年碩士論文

【摘要】：現(xiàn)代戰(zhàn)場環(huán)境中電磁信號形式紛繁復(fù)雜、瞬息萬變,呈現(xiàn)出高密度、多頻段和大帶寬的特點,要求電子偵察接收機(jī)有更好的性能。數(shù)字信道化接收機(jī)具有很大的發(fā)展?jié)摿?但目前其性能還是受到ADC采樣速率與量化位數(shù)的限制,不能同時滿足大動態(tài)范圍和大瞬時帶寬的要求。信號跨信道問題是信道化接收機(jī)必然存在的問題,信道判決和消除虛假輸出技術(shù)是信道化接收中的重要環(huán)節(jié)。用瞬時測頻法消除虛假信號時,由于利用相位法測量頻率,對信號的信噪比要求很高,且當(dāng)單個信道內(nèi)有同時到達(dá)信號時,不能準(zhǔn)確測量出信號的頻率,無法進(jìn)行信道判決。本文針對信道粗略劃分時的信號跨信道問題,研究了一種有效的信道判決方法,先利用信道化瞬時測頻法測量各個信道內(nèi)信號的頻率,再進(jìn)行信道判決,具有同時到達(dá)信號的處理能力。同時,還研究了一種基于FFT的信道化瞬時測頻方法:全相位FFT-相位推算法,該方法先對信號進(jìn)行全相位處理,然后利用FFT實現(xiàn)數(shù)字信道化,準(zhǔn)確測量出各個信道內(nèi)的信號,能夠利用較少的信道劃分,得到較高的測頻精度,且具有多信號處理能力。本文還研究了加窗DFT對頻率測量的影響,討論了不同窗函數(shù)適用的場合:如果單頻信號或多個頻率成分之間幅度差距不大,應(yīng)選用矩形窗函數(shù),DFT分辨率高且主譜線幅度大,易于分離信號和檢測;如果信號中有多個頻率成分且幅度差距較大,則選擇旁瓣電平小的窗函數(shù),防止小信號被大信號的旁瓣淹沒。最后,用FPGA實現(xiàn)了信道化瞬時測頻和信道判決算法,表明算法的有效性和實用性,具有一定的工程應(yīng)用價值。
[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.
【學(xué)位授予單位】：西安電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：TN851

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本文編號：1823569