钻柱信道中声信号传输的接收特性分析

Channel Receiving Characteristics for Transmitted Acoustic Signal in a Drill String

针对周期性管结构信道特征,构建钻柱内一维低频纵波传输的有限差分模型,应用单个加速度传感器作为声接收器,在时、频域仿真分析了换能器接收位置对声信号传输特性的影响规律。在此基础上,考虑信道内多重回波对声通信信号检测的影响,基于信道容量的分析,引入上、下行信道的单位脉冲激励响应,设计了一种基于双声接收器模式的回波噪声抑制方法,并利用倒频谱解析算法,求解接收信号中的回波信息,分析了单、双接收器工作模式下信道响应特征。数值仿真结果表明,双接收模式可有效抑制井下回波噪声,改善信噪比,从而实现更佳的信道接收性能。

According to the channel characteristics of the periodic drill string,a one-dimensional low-frequency longitudinal wave transmission model is established based on the finite-difference algorithm.By using a single accelerometer as an acoustic receiver,the effects of the positions of the receiver on acoustic signal transmission are analyzed using simulations in time and frequency domains.Then,considering the channel capacity with regard to the influences of multi-echoes on acoustic communication signal detections,a dual acoustic receivers-based echo noise suppression method is designed by introducing unit impulse exciting responses of up-going and down-going channels.The cepstrum analysis method is used to extract the echo information from the received acoustic signals.In addition,the characteristics of the channel response on single and dual receivers are analyzed.The numerical simulation results illustrate that the proposed dual-receiver method can effectively suppress underground echo noise and improve the signal-to-noise ratio(SNR),which contributes to better channel receiving performance.