發(fā)布時間：2018-02-08 22:11

  本文關(guān)鍵詞： 單芯電纜 二進(jìn)制頻移鍵控 ???數(shù)模轉(zhuǎn)換器 H橋電路　出處：《電子科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：目前,石油勘探和采集的難度越來越大,井下需要處理的信息越來越多,因此,對測井系統(tǒng)的要求也越來越高。單芯電纜測井系統(tǒng)作為一種典型的生產(chǎn)測井工具,因其體積小成本低而得到廣泛應(yīng)用。但是,單芯電纜較為有限的可用頻帶極大地限制了測井過程中上下行的傳輸速率,同時,井下高溫高壓的嚴(yán)酷環(huán)境也對測井工具的穩(wěn)定性提出了較高要求。本文從測井的實際需求出發(fā),研究了單芯電纜測井系統(tǒng)的一個重要組成部分——單芯電纜高速數(shù)據(jù)傳輸系統(tǒng),并分析了制約其傳輸速率和可靠性的一些關(guān)鍵因素,然后根據(jù)單芯測井系統(tǒng)的特點提出了改進(jìn)方案,并進(jìn)行了設(shè)計和測試。具體的研究內(nèi)容可概括為如下幾點:1、介紹了當(dāng)前單芯電纜的頻率特性,在此基礎(chǔ)上闡述了單芯電纜高速數(shù)據(jù)傳輸系統(tǒng)下行鏈路的數(shù)據(jù)特點和傳輸方式,并采用二進(jìn)制頻移鍵控(2FSK)調(diào)制解調(diào)替代了原有的基帶傳輸形式,不僅簡化了電路結(jié)構(gòu)、減小了系統(tǒng)中的硬件干擾,而且將下行傳輸速率由300bps提升至610bps。2、分析了???數(shù)模轉(zhuǎn)換器的原理,結(jié)合后端電路的MOS管開關(guān)頻率,本文利用耐高溫FPGA對其進(jìn)行了實現(xiàn),完成了對原有鏈路中12bitDAC的替換。這不僅產(chǎn)生了可以驅(qū)動后端高效數(shù)字功放的脈沖寬度調(diào)制(PWM)信號,而且解決了正交頻分復(fù)用(OFDM)調(diào)制方式所產(chǎn)生的信號峰平比較大的問題,同時克服了原DAC不能在高溫下正常工作的弊端。3、利用高速的功率開關(guān)管自行搭建了10MHz開關(guān)頻率的數(shù)字功放驅(qū)動電路、H橋電路和差分低通濾波器,且使數(shù)字功放的效率達(dá)到了86%,滿足了高效性能;另外,本文對該模塊以及整個井下遙傳單元均進(jìn)行了高溫測試,結(jié)果表明在200℃的高溫環(huán)境下該模塊未有明顯失真,且鏈路誤碼率正常,上行速率可以達(dá)到350Kbps。通過上述設(shè)計本文實現(xiàn)了單芯電纜高速數(shù)據(jù)傳輸系統(tǒng)性能的明顯提升,對單芯測井系統(tǒng)的發(fā)展起到了一定的推動作用,同時也為其他領(lǐng)域的同類研究起到了一定的借鑒作用。
[Abstract]:At present, petroleum exploration and acquisition of more and more difficult, more and more information, need to deal with the underground so the logging system requirements are increasingly high. Single core cable logging system as a typical production logging tool, which is widely used because of its small size and low cost. However, the single core cable is the limited available bandwidth greatly limits the transmission rate of logging on the downlink and the harsh environment of high temperature and pressure on the stability of the logging tool is also put forward higher requirements. In this paper, starting from the actual demand of logging, the single core cable logging system is an important part of the single core cable for high-speed data transmission the system, and analyzes some key factors restricting the transmission rate and reliability, then according to the characteristics of single core logging system was put forward the improvement scheme, and the design and test of concrete. The research contents can be summarized as follows: 1, introduces the frequency characteristics of the single core cable, on the basis of the single core cable way downlink high-speed data transmission system and data transmission characteristics, and using binary frequency shift keying (2FSK) modulation and demodulation of baseband transmission instead of the original, not only simplifies the the hardware circuit structure, reduce the interference in the system, and the downlink transmission rate analysis from 300BPS to 610bps.2??? Principle of DAC, with back-end circuit of MOS switching frequency, high temperature resistant FPGA for the realization of the complete replacement of the original 12bitDAC in the link. Not only has a pulse width modulation can drive high back-end digital power amplifier (PWM) signal, but also solves the problem of orthogonal frequency division multiplexing (OFDM) modulation signal generated by the PAPR big problems and overcome The disadvantages of original DAC could not work normally under high temperature.3, using high speed power switching tube built up the digital power amplifier 10MHz switching frequency driving circuit, H bridge circuit and differential low pass filter, and the efficiency of the digital power amplifier has reached 86%, to meet the high performance; in addition, the module and the whole downhole telemetry unit for high temperature test, the results show significant distortion in the high temperature environment under 200 DEG C and the module have the link error rate, uplink rate can reach 350Kbps. by the design of the dramatically improve performance of single core cable in high speed data transmission system, to a certain role in promoting the development of single the core of the logging system, but also to a certain reference for similar research in other fields.

【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P631.83;TN722.75

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本文編號：1496391