中国物理B ›› 2016, Vol. 25 ›› Issue (10): 100502-100502.doi: 10.1088/1674-1056/25/10/100502
Bing-Nan Yan(燕并男), Chong-Xin Liu(刘崇新), Jun-Kang Ni(倪骏康), Liang Zhao(赵亮)
Bing-Nan Yan(燕并男)1,2, Chong-Xin Liu(刘崇新)1, Jun-Kang Ni(倪骏康)1, Liang Zhao(赵亮)3
摘要: In order to grasp the downhole situation immediately, logging while drilling (LWD) technology is adopted. One of the LWD technologies, called acoustic telemetry, can be successfully applied to modern drilling. It is critical for acoustic telemetry technology that the signal is successfully transmitted to the ground. In this paper, binary phase shift keying (BPSK) is used to modulate carrier waves for the transmission and a new BPSK demodulation scheme based on Duffing chaos is investigated. Firstly, a high-order system is given in order to enhance the signal detection capability and it is realized through building a virtual circuit using an electronic workbench (EWB). Secondly, a new BPSK demodulation scheme is proposed based on the intermittent chaos phenomena of the new Duffing system. Finally, a system variable crossing zero-point equidistance method is proposed to obtain the phase difference between the system and the BPSK signal. Then it is determined that the digital signal transmitted from the bottom of the well is ‘0’ or ‘1’. The simulation results show that the demodulation method is feasible.
中图分类号: (Nonlinear dynamics and chaos)