基于內(nèi)插與積分清除濾波的相干DLL性能分析
Performance Analysis of Coherent Delay-Locked Loop Based on Interpolation and Integrate/Dump Filter
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摘要: 提出一種基于內(nèi)插與積分清除濾波的相干延遲鎖定環(huán)(CDLL),用于直接序列碼分多址(DS-CDMA)系統(tǒng)的偽隨機碼跟蹤,并對其進(jìn)行了性能分析。通過將該CDLL定時調(diào)整過程等效為一帶反射壁的齊次馬爾可夫鏈,導(dǎo)出了AWGN與多用戶環(huán)境下定時誤調(diào)整概率、定時均方根抖動、失鎖概率以及平均失鎖時間(MTLL)的表達(dá)式,最后給出了數(shù)值仿真結(jié)果,分析并指出本文的分析結(jié)果同樣適應(yīng)于單徑衰落環(huán)境。該鎖定環(huán)在WCDMA基站系統(tǒng)和移動終端的開發(fā)中得到應(yīng)用。
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關(guān)鍵詞:
- 直接序列碼分多址; 相干延遲鎖定環(huán); 內(nèi)插濾波; 積分清除濾波
Abstract: A Coherent Delay-Locked Loop(CDLL) is proposed based on interpolation and integrate/dump filter for PN code tracking in DS-CDMA systems. The performance of the CDLL is investigated under AWGN and multi-user environments, and closed-form expres-sions for the timing adjustment error probability, steady-state timing squared root error, probability and Mean Time to Lose Lock (MTLL) are derived by employing appropriate Markov chain models. Finally, some numerical results are presented and analysis shows that those results also perform well in single path fading environment. The delay-locked loop is applied to the development of WCDMA BTS and WCDMA MT. -
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