正交幅度调制技术在单芯铠装电缆通讯中的应用

Application of QAM Modulation in Mono-cable Communication

遥传测井仪是连接测井地面与井下仪器的关键仪器,它的核心是对传输数据的调制解调技术。针对单芯铠装电缆信道传输特性差、且电源与通信共同复用缆芯的特点,采用正交幅度调制(QAM)技术设计了单芯高速遥传测井仪,该技术信道带宽利用率高、抗噪声能力强,硬件设计复杂度低,适合应用在空间有限,且工作温度高的恶劣环境中。现场应用表明,该技术能够在较高速率下实现井下与地面的数据通讯,通讯误码率低,抗噪声性能好。

Telemetry logging instrument(TLI)is the key instrument for connecting the ground and downhole instruments in the logging process.MODEM technology is the key part for this tool.Due to the poor transmission of mono-cable channel,and the power supply and communication use the cable core together,this paper uses quadrature amplitude modulation (QAM)technology to design a mono-cable high-speed TLI.This technology has the characteristics of high channel bandwidth utilization,strong anti-noise performance and low hardware design complexity,and is suitable for application in a harsh environment with limited space and high operating temperature.Field application shows that the technology can realize data communication between downhole and ground at a higher rate,with low communication error rate and great anti-noise performance.