本文選題：微弱信號(hào) + 數(shù)字鎖相放大器��； 參考：《中南大學(xué)》2014年碩士論文

【摘要】：摘要：微弱信號(hào)檢測(cè)是隨著工程應(yīng)用而不斷發(fā)展的一門(mén)學(xué)科。近年來(lái),微弱信號(hào)檢測(cè)相關(guān)研究已經(jīng)成為一個(gè)熱點(diǎn)研究領(lǐng)域,具體表現(xiàn)在對(duì)微弱信號(hào)檢測(cè)方法的探尋、對(duì)微弱信號(hào)檢測(cè)系統(tǒng)的設(shè)計(jì)、對(duì)微弱信號(hào)檢測(cè)儀器的研發(fā)。本文中主要研究了利用鎖相放大器進(jìn)行有用信號(hào)提取的微弱信號(hào)檢測(cè)原理與實(shí)現(xiàn)方法。 首先介紹了微弱信號(hào)檢測(cè)的基本理論與常見(jiàn)的幾種檢測(cè)方法,重點(diǎn)介紹了利用數(shù)字鎖相放大器進(jìn)行信號(hào)檢測(cè)的原理。在此基礎(chǔ)上,結(jié)合數(shù)字鎖相放大器的相關(guān)檢測(cè)原理,給出了數(shù)字鎖相放大器的整體設(shè)計(jì)方案,著重從相關(guān)檢測(cè)原理算法和移相算法方面對(duì)數(shù)字鎖相放大器的設(shè)計(jì)作了深入探討。 重點(diǎn)研究了采樣頻率與相關(guān)運(yùn)算結(jié)果的關(guān)系,在設(shè)計(jì)的過(guò)程中先使用MATLAB進(jìn)行算法上的模擬,從模擬結(jié)果發(fā)現(xiàn)參考信號(hào)為方波而采樣頻率與信號(hào)頻率成一定關(guān)系時(shí),系統(tǒng)相關(guān)運(yùn)算存在固有誤差。為減少該誤差,提出了將動(dòng)態(tài)采樣率的方法引入數(shù)字鎖相放大器設(shè)計(jì)中,運(yùn)算發(fā)現(xiàn)動(dòng)態(tài)采樣的采樣頻率數(shù)越多,奇點(diǎn)產(chǎn)生的誤差越少,有效地解決奇點(diǎn)問(wèn)題。 最后,使用Lab VIEW對(duì)設(shè)計(jì)的系統(tǒng)進(jìn)行仿真測(cè)試。測(cè)試結(jié)果表明該數(shù)字鎖相放大器在信號(hào)幅度為5V、噪聲標(biāo)準(zhǔn)差小于等于50時(shí)(SNR=-34.04dB),能有效地檢測(cè)出頻率為500kHz以下的信號(hào),系統(tǒng)檢測(cè)結(jié)果與理論計(jì)算值的相對(duì)誤差基本不超過(guò)2%。
[Abstract]:Absrtact: weak signal detection is a subject developing with engineering application. In recent years, the research on weak signal detection has become a hot research field, which is manifested in the exploration of weak signal detection methods, the design of weak signal detection system and the development of weak signal detection instruments. In this paper, the principle and realization of weak signal detection using PLL amplifier are studied. Firstly, the basic theory of weak signal detection and several common detection methods are introduced, and the principle of signal detection using digital phase-locked amplifier is emphatically introduced. On this basis, combined with the correlation detection principle of the digital phase-locked amplifier, the whole design scheme of the digital phase-locked amplifier is given, and the design of the digital phase-locked amplifier is discussed in detail from the aspects of the correlation detection algorithm and the phase-shifting algorithm. The relationship between sampling frequency and related operation results is studied emphatically. MATLAB is used to simulate the algorithm in the design process. When the reference signal is square wave and the sampling frequency is related to the signal frequency, the simulation results show that the sampling frequency is related to the frequency of the signal. There are inherent errors in the system correlation operation. In order to reduce the error, the method of dynamic sampling rate is introduced into the design of digital phase-locked amplifier. It is found that the more sampling frequency of dynamic sampling, the less the error of singularity, which effectively solves the singularity problem. Finally, LabVIEW is used to simulate and test the designed system. The test results show that the digital phase-locked amplifier can effectively detect signals with a frequency below 500kHz when the signal amplitude is 5V and the noise standard deviation is less than or equal to 50. The relative error between the system test result and the theoretical calculation value is not more than 2.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TN722;TN911.23

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本文編號(hào)：2041945