％ This program calculates radar ranges in a jamming environment. It works
％ with both Stand-off jamming and self-screening jamming for steady and Swerling type
％ targets with frequency agility, coherent integration and standard atmosphere/rain
％ attenuation
Abstract：Noise frequency modulation(FM)jamming。which belongs to blanket jamming。is already become
the main form ofnoise jamming at present。because the wideband was gained by it．Tne spectnlnl ofnoise FM
jamming is analyzed by time domain autocorrelation method in this paper．It’S jamm g peculiarity and幾o(hù)ut—
putting signal’S jamming peculiarity ale explained．At last，these time series models ofnoise FM jalllIIling sig—
nal and幾o(hù)utputting signal ale built．
微弱信號檢測裝置
四川理工學(xué)院 劉鵬飛、梁天德、曾學(xué)明
摘要：
本設(shè)計(jì)以TI的Launch Pad為核心板，采用鎖相放大技術(shù)設(shè)計(jì)并制作了一套微弱信號檢測裝置，用以檢測在強(qiáng)噪聲背景下已知頻率微弱正弦波信號的幅度值，并在液晶屏上數(shù)字顯示出所測信號相應(yīng)的幅度值。實(shí)驗(yàn)結(jié)果顯示其抗干擾能力強(qiáng)，測量精度高。
關(guān)鍵詞：強(qiáng)噪聲；微弱信號；鎖相放大；Launch Pad
Abstract:
This design is based on the Launch Pad of TI core board, using a lock-in amplifier technique designed and produced a weak signal detection device, to measure the known frequency sine wave signal amplitude values of the weak in the high noise background, and shows the measured signal amplitude of the corresponding value in the liquid crystal screen. Test results showed that it has high accuracy and strong anti-jamming capability.
Keywords: weak signal detection; lock-in-amplifier; Launch Pad
1、引言
隨著現(xiàn)代科學(xué)技術(shù)的發(fā)展，在科研與生產(chǎn)過程中人們越來越需要從復(fù)雜高強(qiáng)度的噪聲中檢測出有用的微弱信號，因此對微弱信號的檢測成為當(dāng)前科研的熱點(diǎn)。微弱信號并不意味著信號幅度小，而是指被噪聲淹沒的信號，“微弱”也僅是相對于噪聲而言的。只有在有效抑制噪聲的條件下有選擇的放大微弱信號的幅度，才能提取出有用信號。微弱信號檢測技術(shù)的應(yīng)用相當(dāng)廣泛，在生物醫(yī)學(xué)、光學(xué)、電學(xué)、材料科學(xué)等相關(guān)領(lǐng)域顯得愈發(fā)重要。
2、方案論證
針對微弱信號的檢測的方法有很多，比如濾波法、取樣積分器、鎖相放大器等。下面就針對這幾種方法做一簡要說明。
方案一：濾波法。
在大部分的檢測儀器中都要用到濾波方法對模擬信號進(jìn)行一定的處理，例如隔離直流分量，改善信號波形，防止離散化時(shí)的波形混疊，克服噪聲的不利影響，提高信噪比等。常用的噪聲濾波器有：帶通、帶阻、高通、低通等。但是濾波方法檢測信號不能用于信號頻譜與噪聲頻譜重疊的情況，有其局限性。雖然可以對濾波器的通頻帶進(jìn)行調(diào)節(jié)，但其噪聲抑制能力有限，同時(shí)其準(zhǔn)確性與穩(wěn)定性將大打折扣。
基于CC1110單片機(jī)公交報(bào)站系統(tǒng)主要由CC1110單片機(jī)最小系統(tǒng)和WT588D語音模塊組成，提出了如何實(shí)現(xiàn)語音報(bào)站，通過無線通信SimpliciTI網(wǎng)絡(luò)協(xié)議實(shí)現(xiàn)公交站臺的自動(dòng)播報(bào)和OLCD液晶顯示公交運(yùn)行的各類信息。結(jié)果表明，該公交報(bào)站系統(tǒng)報(bào)站準(zhǔn)確率99%，價(jià)格比同類產(chǎn)品下降了300%以上，系統(tǒng)組成結(jié)構(gòu)簡單，提高了系統(tǒng)的抗干擾性和穩(wěn)定性，也便于攜帶。
Abstract:
The bus stop announcement system based on CC1110 MCU is composed of CC1110 MCU minimum system and WT588D voice module. How to achieve the voice announcing is put forward.The bus-stop will announce automatically and display on the OLCD by means of wireless communication SimpliciTI network protocol. As a result， the bus station stop announcement systems reported 99% accuracy rate， price of similar products declined by 300% or more， system of simple structure， improve the anti-jamming and stability of the power system， it is also portable.
describes the most common terms used in radarsystems, such as range, range resolution, Doppler frequency, and coherency.
The second part of this chapter develops the radar range equation in many of its forms. This presentation includes the low PRF, high PRF,search, bistatic radar, and radar equation with jamming.
Spread-spectrum techniques are methods by which electromagnetic energy generated in a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. These techniques are used for a variety of reasons, including the establishment of secure communications, increasing resistance to natural interference and jamming, and to prevent detec
The goal of this book is to provide a concise but lucid explanation and deriva-
tion of the fundamentals of spread-spectrum communication systems. Although
spread-spectrum communication is a staple topic in textbooks on digital com-
munication, its treatment is usually cursory, and the subject warrants a more
intensive exposition. Originally adopted in military networks as a means of
ensuring secure communication when confronted with the threats of jamming
and interception, spread-spectrum systems are now the core of commercial ap-
plications such as mobile cellular and satellite communication.
The goal of this book is to provide a concise but lucid explanation and deriva-
tion of the fundamentals of spread-spectrum communication systems. Although
spread-spectrum communication is a staple topic in textbooks on digital com-
munication, its treatment is usually cursory, and the subject warrants a more
intensive exposition. Originally adopted in military networks as a means of
ensuring secure communication when confronted with the threats of jamming
and interception, spread-spectrum systems are now the core of commercial ap-
plications such as mobile cellular and satellite communication.
