激光超声波定向传输信道特性测试系统  

Test system of laser ultrasonic directional transmission channel characteristics

作　　者：张培培[1] 谢国坤[1] 王昭[1] ZHANG Peipei;XIE Guokun;WANG Zhao(Zhongxing Communication College,Xi’an Traffic Engineering Institute,Xi'an 710300,China)

机构地区：[1]西安交通工程学院中兴通信学院,西安710300

出　　处：《激光杂志》2020年第11期162-166,共5页Laser Journal

基　　金：陕西省教育厅科研计划项目(No.18JK1042)。

摘　　要：为了增强激光超声波声频信号传输效率,实现激光超声波定向传输,设计一种基于双滑动窗算法的信道特性测试系统。分析激光超声波定向传输原理,选择双边带调制方式,依据Lighthill声散射原则,获取非线性相互作用后生成的差频波声压;通过计算空气非线性作用后差频声音声强,获取激光超声波声频定向传输效率参数,为构建系统创建先决条件;通过信道冲激响应检测算法,使用本地生成PN序列和接收信号生成的峰值,获得CIR矢量;在双滑动窗算法基础上确定门限值,判决区间端点方位,提升信道估计准确度;运用FPGA与DSP器件完成全数字DQPSK解调,采用模数转换板块与接口板块,实现信道特性测试系统构建。仿真结果表明,设计的系统可有效提高激光超声波声频信道的传输精度,且系统数据接收效率较高,拥有很强的实用性与鲁棒性。In order to enhance the transmission efficiency of laser ultrasonic signal and realize laser ultrasonic directional transmission,a channel characteristic test system based on double sliding window algorithm is designed in this paper.This paper analyzes the principle of laser ultrasonic directional transmission,selects the double-sided band modulation mode,obtains the differential frequency wave sound pressure generated after nonlinear interaction according to Lighthill sound scattering principle,obtains the parameters of laser ultrasonic directional transmission efficiency by calculating the differential frequency sound intensity after air nonlinear interaction,and creates the preconditions for construction of system.Through the channel impulse response detection algorithm,the CIR vector is obtained via PN sequence generated locally and peak value generated by receiving signal.The threshold value is determined based on the double sliding window algorithm,the direction of the end point of interval is determined to improve and the accuracy of channel estimation.The digital DQPSK demodulation is completed with FPGA and DSP devices,and the channel characteristic test system is constructed with analog-to-digital conversion board and interface board.The simulation results show that the designed system can effectively improve the transmission accuracy of laser ultrasonic audio channel,and the system has high efficiency of data reception,strong practicability and robustness.

关 键 词：激光超声波 定向传输 信道特性 双滑动窗算法 PN序列 CIR矢量 

分 类 号：TN936[电子电信—信号与信息处理]