發(fā)布時(shí)間：2018-04-28 08:16

  本文選題：Chirp + 線性調(diào)頻信號(hào)�。� 參考：《華南理工大學(xué)》2015年碩士論文

【摘要】：超聲探測(cè)作為當(dāng)下運(yùn)用最為廣泛的探測(cè)技術(shù),因其無損特性,被廣泛應(yīng)用于工業(yè)探傷,醫(yī)療、交通運(yùn)輸?shù)阮I(lǐng)域。線性調(diào)頻信號(hào)是數(shù)字信號(hào)處理領(lǐng)域的一種非常重要的信號(hào),因其大時(shí)寬帶寬積特性,被經(jīng)常應(yīng)用到超聲探測(cè)中。在現(xiàn)實(shí)情況下信道都是非理想的,通過超聲探頭檢測(cè)得到的接收數(shù)據(jù)已經(jīng)受到了其探頭自身信道的干擾,使得接收數(shù)據(jù)并不精準(zhǔn),所以研究信道的估計(jì)與均衡算法并將其應(yīng)用在超聲探測(cè)系統(tǒng)中,對(duì)提高檢測(cè)系統(tǒng)的數(shù)據(jù)精度具有重要意義。本文基于線性調(diào)頻信號(hào)提出一種新的信道估計(jì)與均衡算法并將其進(jìn)行仿真與實(shí)驗(yàn)驗(yàn)證。本文首先對(duì)傳統(tǒng)的LMS信道均衡算法做了理論分析和研究,并對(duì)最優(yōu)解的三種求解方式做了綜述。接著本文重點(diǎn)研究針對(duì)于線性調(diào)頻信號(hào)提出的基于頻域的信道估計(jì)均衡算法和基于頻域加窗的時(shí)延估計(jì)改進(jìn)算法。本文通過分別對(duì)以上兩種算法進(jìn)行數(shù)學(xué)上的理論推導(dǎo),并且通過仿真,證實(shí)了其有效性。同時(shí),對(duì)影響基于頻域的信道估計(jì)均衡算法的性能參數(shù):步長(zhǎng)、迭代次數(shù)、初始值的設(shè)置進(jìn)行的比較和分析;在不同信噪比下對(duì)基于頻域加窗的時(shí)延估計(jì)改進(jìn)算法的效果與原算法進(jìn)行對(duì)比,通過仿真證實(shí)改進(jìn)算法的有效性。在本文的最后一章中,運(yùn)用第四章提出的基于頻域的信道估計(jì)均衡算法進(jìn)行實(shí)驗(yàn),用來提高超聲檢測(cè)系統(tǒng)的檢測(cè)精度。不同的探頭具有不同的物理特性,通過檢測(cè)發(fā)射與接收探頭直接對(duì)接時(shí)的數(shù)據(jù)可以對(duì)探頭自身信道進(jìn)行估計(jì),從而對(duì)接收數(shù)據(jù)進(jìn)行均衡處理,使實(shí)際接收數(shù)據(jù)與理想接收數(shù)據(jù)的誤差降低,提高檢測(cè)系統(tǒng)的精確度。在本文中,對(duì)基于線性調(diào)頻信號(hào)的信道估計(jì)與均衡算法從理論推導(dǎo)到仿真結(jié)果整個(gè)過程中,算法的有效性得到充分的驗(yàn)證,并且通過實(shí)驗(yàn)結(jié)果表明,本文提出的信道估計(jì)與均衡算法具有實(shí)際的效用。
[Abstract]:As the most widely used detection technology, ultrasonic detection is widely used in industrial detection, medical treatment, transportation and other fields because of its nondestructive characteristics. Linear frequency modulation signal is a very important signal in the field of digital signal processing. Because of its large time broadband and wide product characteristics, it is often applied to ultrasonic detection. The channel is not ideal. The receiving data obtained through the ultrasonic probe has been disturbed by the channel of its probe, which makes the received data imprecise. Therefore, it is of great significance to study the estimation and equalization algorithm of the channel and apply it to the ultrasonic detection system. This paper is based on linear analysis. FM signal presents a new channel estimation and equalization algorithm and carries out simulation and experimental verification. Firstly, this paper makes a theoretical analysis and Research on the traditional LMS channel equalization algorithm, and summarizes the three ways of solving the optimal solution. Then, this paper focuses on the frequency domain based channel proposed for linear FM signals. The estimation of the equilibrium algorithm and the improved algorithm based on the frequency-domain window based time delay estimation. In this paper, the theoretical derivation of the above two algorithms is mathematically deduced and its effectiveness is verified by simulation. At the same time, the ratio of the performance parameters of the channel estimation equalization algorithm based on the frequency domain: step length, iteration number and initial value are compared. Compared with the analysis, the effectiveness of the improved algorithm based on the frequency domain plus window based time delay estimation is compared with the original algorithm, and the effectiveness of the improved algorithm is verified by simulation. In the last chapter of this paper, the experiment based on the channel estimation equalization algorithm based on the frequency domain proposed in the fourth chapter is used to improve the detection of the ultrasonic detection system. Measurement accuracy. Different probes have different physical characteristics. By detecting the data of the probe directly connected to the receiving probe, the probe can estimate the channel of the probe itself, so as to balance the received data, so that the error of the actual received data and the ideal received data is reduced and the accuracy of the detection system is improved. In this paper, the base In the whole process of the channel estimation and equalization algorithm of LFM signals from theory to simulation results, the effectiveness of the algorithm is fully verified, and the experimental results show that the proposed channel estimation and equalization algorithm has practical utility.

【學(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN911.5

【參考文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前3條

1 王瑋;非線性等式約束優(yōu)化問題的一類既約Hessian算法研究[D];首都師范大學(xué);2007年

2 孟小猛;自適應(yīng)濾波算法研究及應(yīng)用[D];北京郵電大學(xué);2010年

3 劉璋麟;基于線性調(diào)頻信號(hào)的時(shí)延估計(jì)算法研究及其在液體檢測(cè)中的應(yīng)用[D];華南理工大學(xué);2014年

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本文編號(hào)：1814496