摘 要：构建了钻柱内一维低频纵波传输的有限差分模型，时域和频域仿真分析了换能器位置和载波信号对周期性管结构信道内声传输信号的影响规律，设计了时延脉冲OOK信号调制方法。采用窄脉冲调制信号激励方式，沿管轴方向对有限长模拟钻柱施加纵向激励，进行了测试信号的声传输实验。结果表明，在1W激振功率、77bit/s传输速率和长6.44m模拟钻柱信道的传输条件下，该方法可实现实验室内测试信号的低频声波传输与信号检测，为井下参数的钻柱声遥测系统设计提供理论与试验基础。

Abstract: A finite-differential model for the one-dimensional propagation of longitudinal waves along the drill string is established. The influences of acoustic transducer positions and carrier wave signals on acoustic transmission signals in the periodic pipe structure transmission channel are analyzed by the time and frequency domain simulation. An on-off keyed (OOK) modulation of time-delayed pulses is designed. Then, the narrow pulse modulated signal transmission experiments are performed by applying the longitudinal excitation to the length-limited simulated drill string in the axial direction of pipes. The results show that under the conditions of excitation power of 1W, transmission rate of 77 bit/s and 6.44-meter simulated drill string, the proposed transmission method can implement the data transmission and signal detection of test signals via low-frequency extensional waves in the laboratory. Moreover, the simulation and experimental research on acoustic wave propagation along the drill string provides the theoretical and trial foundation for the design of downhole acoustic telemetry system.