本文關(guān)鍵詞：TDR差分測量方法與多點校準技術(shù)研究與軟件實現(xiàn)　出處：《電子科技大學》2014年碩士論文　論文類型：學位論文

  更多相關(guān)文章： 特性阻抗測試 等效偽差分 多點校準 數(shù)據(jù)庫

【摘要】：TDR特性阻抗測試儀是一款利用時域反射法測量阻抗不連續(xù)點處特性阻抗的儀器,適用于電路板制造商對PCB跡線進行出廠前質(zhì)量檢驗。目前項目組自主研發(fā)成功了Asida系列特性阻抗測試儀器,但是在核心的校準與測量技術(shù)上面還不夠完善,需要進一步的優(yōu)化,來提高整個系統(tǒng)的測量精度。本論文以提高特性阻抗測試儀的精度為目標,主要工作內(nèi)容有以下幾方面:首先,根據(jù)時域反射計(TDR)的基本原理和儀器需要實現(xiàn)的功能,制定TDR特性阻抗測試儀的總體方案,并根據(jù)總體方案利用面向?qū)ο蠼y(tǒng)一建模語言UML進行軟件需求分析建模和軟件設(shè)計分析建模;第二,分析對比目前業(yè)界的差分測量算法,根據(jù)自身硬件條件選擇了對硬件要求較低,只需單脈沖源和單取樣頭,但對軟件算法要求較高的等效偽差分測試算法,這種差分測試方法不僅降低了開發(fā)成本,并且測量結(jié)果也在允許的誤差范圍內(nèi);第三,提出了一種改進的校準方法,將傳統(tǒng)的兩點校準改進為多點校準,測量誤差比傳統(tǒng)方法降低了2%,傳統(tǒng)方法的誤差為5%,并將改進的校準方法和等效偽差分測量算法在特性阻抗測試儀中實現(xiàn);第四,重新設(shè)計了特性阻抗測試儀的數(shù)據(jù)存儲模塊,采用了數(shù)據(jù)庫管理方案彌補了文檔管理方式的缺陷,為項目的進一步發(fā)展提供了數(shù)據(jù)存儲空間保證;最后,總結(jié)了影響特性阻抗測量精度的幾個因素,并給出了解決方案,確保整個系統(tǒng)能夠提供更精確的測量服務(wù)。本文的校準與測試算法以及數(shù)據(jù)存儲方法均是在VC++平臺上實現(xiàn),并根據(jù)項目需要實現(xiàn)的目標,聯(lián)合硬件平臺進行聯(lián)調(diào)測試。經(jīng)過大量的實際測量實驗,將本文結(jié)果與泰克、polar等國外儀器的測量結(jié)果進行了比較和分析,驗證了等效偽差分測量方法和多點校準技術(shù)的正確性。數(shù)據(jù)存儲模塊,實現(xiàn)了校準測量數(shù)據(jù)穩(wěn)定存取、檢索和動態(tài)擴容,解決了測量數(shù)據(jù)量大的存儲問題。目前該款軟件和儀器配合使用的Asida第三代產(chǎn)品能夠自動化、批量化、快速、準確地對PCB跡線進行測試,且已經(jīng)通過系統(tǒng)功能測試和性能測試可以提供給電路板制造商使用,此外系統(tǒng)還有任務(wù)管理,波形分析,數(shù)據(jù)顯示,結(jié)果分析等功能。
[Abstract]:The TDR characteristic impedance tester is a kind of instrument which uses time domain reflectance method to measure the characteristic impedance at the point of impedance discontinuity. It is suitable for the PCB manufacturer to carry on the pre-factory quality inspection to the PCB trace. At present, the project team has independently developed the Asida series characteristic impedance test instrument. However, the core calibration and measurement technology is not perfect, and further optimization is needed to improve the measurement accuracy of the whole system. This paper aims to improve the accuracy of the characteristic impedance tester. The main work is as follows: firstly, according to the basic principle of time-domain reflectometer (TDR) and the functions that the instrument needs to realize, the overall scheme of TDR characteristic impedance tester is established. According to the overall scheme, software requirement analysis modeling and software design analysis modeling are carried out by using object-oriented unified modeling language (UML). Second, the analysis and comparison of the current industry differential measurement algorithm, according to their own hardware conditions to select the hardware requirements are low, only need a single pulse source and single sampling head. But the equivalent pseudo difference testing algorithm which requires higher software algorithm not only reduces the development cost but also results within the allowable error range. Thirdly, an improved calibration method is proposed. The traditional two-point calibration is improved to multi-point calibration. The measurement error is reduced by 2% compared with the traditional method, and the error of the traditional method is 5%. The improved calibration method and the equivalent pseudo-difference measurement algorithm are implemented in the characteristic impedance tester. In 4th, the data storage module of the characteristic impedance tester was redesigned, and the database management scheme was adopted to make up the defect of the document management mode, which provided the data storage space guarantee for the further development of the project. Finally, several factors affecting the precision of characteristic impedance measurement are summarized, and the solutions are given. To ensure that the whole system can provide more accurate measurement services. The calibration and testing algorithms and data storage methods are implemented on VC platform, and according to the project needs to achieve the goal. Through a large number of practical measurement experiments, the results of this paper are compared and analyzed with the measurement results of foreign instruments such as Tek polar and so on. The validity of the equivalent pseudo-differential measurement method and multi-point calibration technology is verified. The data storage module realizes the stable access, retrieval and dynamic expansion of calibration measurement data. It solves the storage problem of large amount of measurement data. At present, the third generation of Asida products, which are used together with the software and instruments, can automate, batch, quickly and accurately test the PCB trace line. In addition, the system also has functions of task management, waveform analysis, data display, result analysis and so on.
【學位授予單位】：電子科技大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TM934.7

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本文編號：1395873