准单次正交互补Golay码超声编解码方法研究  

Research on ultrasonic encoding and decoding method for quasi single orthogonal complementary Golay codes

作　　者：刘桂雄[1,2] 唐文明[1,2] 纪轩荣 

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640 [2]广州市事故模拟仿真与物证溯源技术重点实验室,广州510641 [3]广州多浦乐电子科技有限公司,广州510330

出　　处：《仪器仪表学报》2016年第6期1309-1315,共7页Chinese Journal of Scientific Instrument

基　　金：国家重大科学仪器设备开发专项(2013YQ230575);广州市科技计划项目(201509010008)资助

摘　　要：正交互补Golay(A、B)码是重要的超声相控阵系统编码激励码型,但两次激励可能会存在相对扫查位置变化而导致会影响解码性能,本文研究一种准单次正交互补Golay码超声编解码方法,该方法基于二元调相(0、π)理想编解码公式和AB激励转换因子的推导,实现A码一次实际激励而形成A、B码两次激励的效果,既可避免两次激励可能存在的问题又发挥了单次激励简单成熟优点,进一步设计了降噪解码模型,有效地降低了反卷积运算对噪声敏感度。通过加性高斯白噪声(AWGN)对整个系统进行仿真测试和基于现场可编程门阵列(FPGA)的实际测试,对8位Golay码进行准单次编码激励仿真测试降噪下就能获得20 d B的信噪比增益。最后,本文介绍了应用该方法的超声相控阵仪器在高难穿透材料的自动化检测的实验结果。The orthogonal complementary Golay （A, B） code is one type of important code pattern in the category of the ultrasonic phased array system. However, the double excitations can lead to negative decoding performance due to the relative change of scanning positions. Hence, this paper studies one type of quasi single orthogonal complementary Golay code to overcome this drawback. The proposed approach relies on the ideal decoding formulation of binary phase modulation （0, π） and the deduction of A←→B conversion factor. The research realizes the once real excitation of A code which has the same performance as the twice excitation effectiveness with A and B code. In this way, it can not only avoid the potential problems produced by the twice excitation, but it also has the advantages of simpleness and the maturity of once exciting. Then, a noise reduction and decoding model is designed in further to effectively weaken the sensitivity of the noise which is caused by deconvolution. By implementing simulations of the whole system with Additive White Gaussian Noise （AWGN） and the practical measure on Field Programmable Gate Array （FPGA）, 20dB signal to noise ratio can be achieved by once encoding excitation of the 8 bit Golay codes of. Finally, the paper also introduces the experimental results about the application of the proposed approach on the automatic testing of the ultrasonic phased array instrument which is hard to be penetrated.

关 键 词：正交互补Golay码 准单次发射 反卷积 现场可编程门阵列 

分 类 号：TH878.2[机械工程—仪器科学与技术] R319[机械工程—精密仪器及机械]