微弱信號(hào)檢測(cè)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(hào)檢測(cè)裝置，用以檢測(cè)在強(qiáng)噪聲背景下已知頻率微弱正弦波信號(hào)的幅度值，并在液晶屏上數(shù)字顯示出所測(cè)信號(hào)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(cè)量精度高。
關(guān)鍵詞：強(qiáng)噪聲；微弱信號(hào)；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(guò)程中人們?cè)絹?lái)越需要從復(fù)雜高強(qiáng)度的噪聲中檢測(cè)出有用的微弱信號(hào)，因此對(duì)微弱信號(hào)的檢測(cè)成為當(dāng)前科研的熱點(diǎn)。微弱信號(hào)并不意味著信號(hào)幅度小，而是指被噪聲淹沒(méi)的信號(hào)，“微弱”也僅是相對(duì)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(hào)的幅度，才能提取出有用信號(hào)。微弱信號(hào)檢測(cè)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(duì)微弱信號(hào)的檢測(cè)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(duì)這幾種方法做一簡(jiǎn)要說(shuō)明。
方案一：濾波法。
在大部分的檢測(cè)儀器中都要用到濾波方法對(duì)模擬信號(hào)進(jìn)行一定的處理，例如隔離直流分量，改善信號(hào)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(cè)信號(hào)不能用于信號(hào)頻譜與噪聲頻譜重疊的情況，有其局限性。雖然可以對(duì)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。
針對(duì)目前汽車追尾事件頻發(fā)問(wèn)題，提出一種防汽車車前和車后追尾的安全裝置設(shè)計(jì)。該設(shè)計(jì)以高性能、低功耗的8位AVR微處理器ATmega8L為核心，結(jié)合霍爾式車速傳感器、激光雷達(dá)測(cè)距裝置和MMA7260QT加速度傳感器，能夠兼顧車前和車后，摒棄以往設(shè)計(jì)中只考慮車前或車后單一性缺點(diǎn)，尤其適用于高速、夜晚或新手行車。
Abstract:
Aiming at the high frequency of vehicle rear-end collision，a safe device design of anti-vehicle rear-end collision is presented.In the design，the high-performance，low-power8-bit AVR microprocessor ATmega8L is utilized as a core combined with Hall-type speed sensor，laser-radar ranging devices and the acceleration sensor MMA7260QT.The design considers both the front and back of a car，and overcomes the drawbacks of former designs in which only the front or the back of the car is considered，so it is especially suitable for high-speed，night or the beginner’s driving.
介紹一種以Atmel公司的Attiny13為處理器的投影儀防盜器設(shè)計(jì)方案。該防盜器具有功耗低，功能完整，防盜效果良好等特點(diǎn)，除具有報(bào)警功能外，防盜器還具有以無(wú)線方式向主機(jī)發(fā)送報(bào)警信號(hào)的功能。采用315MHz發(fā)射模塊實(shí)現(xiàn)無(wú)線信號(hào)發(fā)送。該投影儀防盜器可適應(yīng)眾多廠家生產(chǎn)的防盜器主機(jī)。
Abstract:
This paper introduces the design scheme of overhead projector's anti-theft device which users ATMEL company’s Attiny13as processor.This anti-theft device features low powerloss，functional integrity，good effect of anti-theft.In addition to its own with alarm functions，the anti-theft device also has alarm function which can send alarm signal to the host through wireless way.It sends wireless signal using315MHz transmitting module，so this overhead projector’s anti-theft device is adapted to anti-theft device host produced by many manufacturers.
介紹了一種基于C8051F020單片機(jī)的多路壓力測(cè)量?jī)x。該測(cè)量?jī)x選用電阻應(yīng)變式壓力傳感器采集壓力信號(hào)，并經(jīng)放大電路處理后送入C8051F020單片機(jī)，再由C8051F020單片機(jī)內(nèi)部的A/D轉(zhuǎn)換器將采集到的壓力信號(hào)進(jìn)行模數(shù)轉(zhuǎn)化，然后分別對(duì)數(shù)據(jù)進(jìn)行存儲(chǔ)和顯示。該測(cè)量?jī)x能測(cè)量6路壓力信號(hào)，并且各測(cè)量點(diǎn)都能單獨(dú)檢測(cè)和設(shè)置。由于采用了C8051F020單片機(jī)，簡(jiǎn)化了硬件電路，增強(qiáng)了抗干擾能力，使得測(cè)量?jī)x具有測(cè)量精度高，沖擊小等特點(diǎn)。
Abstract:
A measurement apparatus for multi-channel pressure based on single chip microcomputer is introduced.It can measure 6 channels signal of the pressure，and the pressure measure points can be detection and located individually.The pressure signal sampling is obtained by resistor stress-type pressure sensors，the digital signals of 6 channels are collected through amplifying and adjustment circuit of pressure signals and internal integrated A/D converter of MCU.Finally，and it realizes the function to store and display data separately.C8051F020 was used to made hardware circuit simple，and it also enhanced the anti-interference ability.It features high precision and little impact.
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(yǔ)音模塊組成，提出了如何實(shí)現(xiàn)語(yǔ)音報(bào)站，通過(guò)無(wú)線通信SimpliciTI網(wǎng)絡(luò)協(xié)議實(shí)現(xiàn)公交站臺(tái)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(jiǎn)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.
