基于開關(guān)電容技術(shù)的鎖定放大器設(shè)計(jì)
所屬分類:技術(shù)論文
上傳者:serena
標(biāo)簽: 鎖定放大器 開關(guān)電容
所需積分:1分積分不夠怎么辦,?
文檔介紹:鎖定放大是微弱信號檢測的重要手段,。基于相關(guān)檢測理論,,利用開關(guān)電容的開關(guān)實(shí)現(xiàn)鎖定放大器中乘法器的功能,,提出開關(guān)電容和積分器相結(jié)合以實(shí)現(xiàn)相關(guān)檢測的方法,,并設(shè)計(jì)出一種鎖定放大器。該鎖定放大器將微弱信號轉(zhuǎn)化為與之相關(guān)的方波,,通過后續(xù)電路得到正比于被測信號的直流電平,,為后續(xù)采集處理提供方便,。測量數(shù)據(jù)表明鎖定放大器前級可將10-6 A的電流轉(zhuǎn)換為10-1 V的電壓,后級通過帶通濾波器級聯(lián)可將信號放大1×105倍,。該方法在降低噪聲的同時,,可對微弱信號進(jìn)行放大,線性度較高,、穩(wěn)定性較好,。 Lock-in Amplifying(LIA)is one of important means for weak signal detection. Based on cross-correlation detection theory, switch in the swithched capacitor was used as multiplier of LIA,, and a new method of correlation detection was proposed combining swithched capacitor with integrator. A kind of LIA was designed which can convert the weak signal to square-wave,, then DC proportional to measured signal was obtained through follow-up conditioning circuit, providing convenience for signal acquisition and processing. The measured data shows that the electric current(10-6 A) can be changed into voltage(10-1 V) by LIA,, and the signal is magnified 1×105 times by cascade band-pass filter. The noise is suppressed and the w
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