1. Faculty of Electronic and Information Engineering, West Anhui University, Lu’an 237012, P. R. China
2. School of Physics and Electronic Information, Gannan Normal University, Normal University South Road Rongjiang, New District, Ganzhou City, Jiangxi Province 341000, P. R. China
3. Faculty of Electronic and Information Engineering, West Anhui University, Lu’an, Anhui Province, 237010, P. R. China