单芯电缆高速通讯下行链路的数据传输及高效功率放大器的设计

发布时间：2018-02-08 22:11

本文关键词： 单芯电缆二进制频移键控 ???数模转换器 H桥电路　出处：《电子科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,石油勘探和采集的难度越来越大,井下需要处理的信息越来越多,因此,对测井系统的要求也越来越高。单芯电缆测井系统作为一种典型的生产测井工具,因其体积小成本低而得到广泛应用。但是,单芯电缆较为有限的可用频带极大地限制了测井过程中上下行的传输速率,同时,井下高温高压的严酷环境也对测井工具的稳定性提出了较高要求。本文从测井的实际需求出发,研究了单芯电缆测井系统的一个重要组成部分——单芯电缆高速数据传输系统,并分析了制约其传输速率和可靠性的一些关键因素,然后根据单芯测井系统的特点提出了改进方案,并进行了设计和测试。具体的研究内容可概括为如下几点:1、介绍了当前单芯电缆的频率特性,在此基础上阐述了单芯电缆高速数据传输系统下行链路的数据特点和传输方式,并采用二进制频移键控(2FSK)调制解调替代了原有的基带传输形式,不仅简化了电路结构、减小了系统中的硬件干扰,而且将下行传输速率由300bps提升至610bps。2、分析了???数模转换器的原理,结合后端电路的MOS管开关频率,本文利用耐高温FPGA对其进行了实现,完成了对原有链路中12bitDAC的替换。这不仅产生了可以驱动后端高效数字功放的脉冲宽度调制(PWM)信号,而且解决了正交频分复用(OFDM)调制方式所产生的信号峰平比较大的问题,同时克服了原DAC不能在高温下正常工作的弊端。3、利用高速的功率开关管自行搭建了10MHz开关频率的数字功放驱动电路、H桥电路和差分低通滤波器,且使数字功放的效率达到了86%,满足了高效性能;另外,本文对该模块以及整个井下遥传单元均进行了高温测试,结果表明在200℃的高温环境下该模块未有明显失真,且链路误码率正常,上行速率可以达到350Kbps。通过上述设计本文实现了单芯电缆高速数据传输系统性能的明显提升,对单芯测井系统的发展起到了一定的推动作用,同时也为其他领域的同类研究起到了一定的借鉴作用。
[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.

【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.83;TN722.75

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