本文選題：譜線檢測 + 稀疏信號(hào)��； 參考：《云南大學(xué)》2015年碩士論文

【摘要】：譜線檢測是射電天文觀測的關(guān)鍵技術(shù)之一。根據(jù)觀察到的星體譜線,可以了解星體的一些重要特征,比如運(yùn)行軌跡、總粒子數(shù)密度、年齡等。這些特征所對(duì)應(yīng)的分子輻射譜線載頻位置極高,都在GHz量級(jí)以上�；趥鹘y(tǒng)高速數(shù)據(jù)采集的射電天文終端設(shè)備存在很多局限性,無法很好地滿足天文學(xué)家同時(shí)觀測更多譜線和同時(shí)觀測頻率相差很遠(yuǎn)的分子多個(gè)轉(zhuǎn)動(dòng)躍遷的要求。 射電天文信號(hào)是在頻域上稀疏的信號(hào)。壓縮感知理論正是針對(duì)在某個(gè)域上稀疏的信號(hào)提出的,該理論可以解決傳統(tǒng)采樣在高頻信號(hào)采集中ADC采樣率高和數(shù)據(jù)存儲(chǔ)容量大的問題。基于壓縮感知理論的信號(hào)采集把采樣過程和壓縮過程合二為一,以較低的采樣率采樣得到較少的數(shù)據(jù),最后通過求解最優(yōu)問題來對(duì)原始稀疏信號(hào)進(jìn)行重構(gòu)。隨機(jī)解調(diào)器、多倍集采樣和調(diào)制寬帶轉(zhuǎn)換器三種壓縮采樣模型的提出使得壓縮感知理論進(jìn)入實(shí)用階段。 論文對(duì)隨機(jī)解調(diào)器信號(hào)采樣與重構(gòu)理論進(jìn)行分析研究,在仿真實(shí)驗(yàn)的基礎(chǔ)上,設(shè)計(jì)了硬件電路,并通過FPGA實(shí)現(xiàn)隨機(jī)解調(diào)器采樣與重構(gòu)。首先,論文介紹了壓縮感知的基本原理,包括壓縮感知理論的三大核心問題以及三種壓縮采樣模型。其次,論文深入分析了隨機(jī)解調(diào)器信號(hào)采樣與重構(gòu)方法,并進(jìn)行了算法仿真實(shí)驗(yàn)。最后,設(shè)計(jì)了硬件電路實(shí)現(xiàn)隨機(jī)解調(diào)器。硬件電路包括如下幾個(gè)部分：信號(hào)預(yù)處理部分通過精心挑選合適的芯片并對(duì)每個(gè)模塊進(jìn)行仿真驗(yàn)證后設(shè)計(jì)制作了相應(yīng)的電路板；信號(hào)采樣與數(shù)據(jù)緩存通過FPGA對(duì)ADC和SDRAM控制完成；原始信號(hào)的稀疏矢量重構(gòu)利用OMP算法,首先對(duì)OMP算進(jìn)行改進(jìn),然后在設(shè)計(jì)中通過資源復(fù)用、并行計(jì)算和避開復(fù)雜運(yùn)算(如開方運(yùn)算)等方法在FPGA上優(yōu)化設(shè)計(jì)實(shí)現(xiàn),既加快了運(yùn)算速度又減少硬件電路的復(fù)雜度。 對(duì)隨機(jī)解調(diào)器的仿真驗(yàn)證了系統(tǒng)的可行性。硬件實(shí)現(xiàn)的隨機(jī)解調(diào)器系統(tǒng)充分利用了FPGA并行計(jì)算的優(yōu)勢,能以較低的采樣率對(duì)頻域稀疏信號(hào)進(jìn)行采樣并對(duì)其進(jìn)行譜線觀測。實(shí)驗(yàn)結(jié)果表明,該系統(tǒng)實(shí)現(xiàn)了壓縮采樣,以40MHz的采樣率成功的對(duì)最高頻率為80MHz的信號(hào)進(jìn)行譜線檢測。
[Abstract]:Spectral line detection is one of the key techniques in radio astronomical observation. According to the observed spectral lines of the stars, some important characteristics of the stars can be understood, such as trajectory, total particle density, age and so on. These characteristics correspond to the extremely high carrier frequency positions of the molecular radiation lines, all of which are of the order of magnitude above GHz. The radio astronomical terminal equipment based on the traditional high-speed data acquisition has many limitations, which can not meet the requirements of the astronomer to observe more spectral lines at the same time and to observe many rotational transitions of molecules with far different frequency simultaneously. Radio astronomical signals are sparse signals in frequency domain. Compression sensing theory is proposed for sparse signals in a certain domain. This theory can solve the problems of high ADC sampling rate and large data storage capacity in traditional sampling in high frequency signal acquisition. The signal acquisition based on compression sensing theory combines the sampling process with the compression process, and obtains less data at a lower sampling rate. Finally, the original sparse signal is reconstructed by solving the optimal problem. Three compression sampling models, random demodulator, multi-fold sampling and modulation wideband converter, have brought the theory of compression sensing into practical stage. In this paper, the theory of signal sampling and reconstruction of random demodulator is analyzed and studied. On the basis of simulation experiment, the hardware circuit is designed, and the sampling and reconstruction of random demodulator is realized by FPGA. Firstly, the basic principle of compression sensing is introduced, including three core problems of compression sensing theory and three compression sampling models. Secondly, the method of sampling and reconstruction of random demodulator signal is deeply analyzed, and the algorithm simulation experiment is carried out. Finally, the hardware circuit is designed to realize the random demodulator. The hardware circuit includes the following parts: the signal preprocessing part designs and manufactures the corresponding circuit board after selecting the appropriate chip carefully and carries on the simulation verification to each module, the signal sampling and the data cache control the ADC and the SDRAM through the FPGA to complete; The sparse vector reconstruction of the original signal uses OMP algorithm to improve the OMP calculation first, and then optimizes the design on FPGA by means of resource reuse, parallel computing and avoiding complex operation (such as square operation). It not only speeds up the operation speed but also reduces the complexity of the hardware circuit. The simulation of the random demodulator verifies the feasibility of the system. The hardware implementation of the stochastic demodulator system makes full use of the advantages of FPGA parallel computing, and can sample the sparse signals in frequency domain at a low sampling rate and observe the spectral lines. The experimental results show that the system realizes the compression sampling and successfully detects the spectral lines of the signals with the highest frequency of 80MHz at the sampling rate of 40MHz.
【學(xué)位授予單位】：云南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN763

【參考文獻(xiàn)】

相關(guān)期刊論文 前5條

1 周殿鳳;王俊華;;基于FPGA的32位除法器設(shè)計(jì)[J];信息化研究;2010年03期

2 秦定宇;王敬東;李鵬;;圖像融合中小波基的選擇分析[J];光電子技術(shù);2006年03期

3 韓春;蔡俊;;基于FPGA的高速偽隨機(jī)序列發(fā)生器設(shè)計(jì)[J];電子測量技術(shù);2013年07期

4 莫禹鈞;柏正堯;黃振;董亮;周燕;;正交匹配追蹤算法的優(yōu)化設(shè)計(jì)與FPGA實(shí)現(xiàn)[J];電子技術(shù)應(yīng)用;2014年10期

5 莫禹鈞;柏正堯;黃振;周燕;閆帥輝;;基于隨機(jī)解調(diào)器的射電天文信號(hào)的采樣與恢復(fù)算法[J];南陽理工學(xué)院學(xué)報(bào);2014年03期

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本文編號(hào)：2070504